Sunday, March 06, 2011

First Asda price guarantee analysis

This is the first stage in my quest to extract more value from the ASDA Price Guarantee...

I'll say up front that I think ASDA are overall cheaper for my shopping and that I appreciate what they're doing with this guarantee.

The ASDA Price Guarantee says "We'll guarantee your comparable grocery shopping is 10% cheaper at ASDA or we'll give you the difference".

They currently compare against Tesco, Morrisons, Sainsburys and Waitrose.  If ASDA are not 10% cheaper then they issue you a voucher for the difference which can be used against a future ASDA purchase.

It is important to note that it is the total value of the trolley/order that is compared, not each individual item.

This means that whenever Asda is cheaper, the "saving" is effectively offset against when it is not cheapest.

An example may help illustrate the point.  Consider an order with 2 items: Bread and Milk (you actually must have 8 different items in an order to qualify, but only one of them needs to have a comparable product at another store)

Bread... ASDA: £0.70, Tesco: £1.00

Milk.... ASDA: £1.10, Tesco: £1.00

The total cost of the Tesco order is £2.00 and Asda is £1.80. ASDA are 10% cheaper so no refund voucher is due.

But if the order could have been split in to 2 orders, the Bread order would have no refund but the Milk order would have resulted in a 20p voucher.

My shopping trolleys have so far resulted in either no refund or refunds of relatively small amounts like £1.50 on a £100 shop - certainly worth having but not 10%.

Looking at the comparison tables it is clear that if you could avoid mixing the good value items in with the poor value items then more savings could be made.

On our most recent shop we got 2 trolleys: one for what looked like good value items, one that looked like normal prices.  We did not do any formal research on prices before we started.  If we could have perfect knowledge of the prices then this would all be really easy, but in the Real World that info isn't very quick to obtain.

Update: I think this is new... mySupermarket now have a Quick Shop search which lets you see the prices for a single item. I successfully used it from my iPhone the other day when looking at lasagne sauce. They had Dolmio reduced from £1.66 to £1.00, or an own brand for £0.96   A quick search showed that Tesco were offering it on BOGOF at £1.76  So I bought 2 for £2.00 and the price guarantee shows that I could have got 2 for £1.76, so my voucher includes the 24p I overspent and an additional 10% of £1.76 = 18p. So I got 2 Dolmio sauces for £1.58 which is a good price.

2 Trolleys, 2 Vouchers

"bargains" trolley: 27p voucher from £43.55 - 0.62%
Normal trolley: £1.70 voucher on £75.09 - 2.26%

So far I've only been analysing the "bargains" trolley. The website shows you some info on the basket totals at each store and you can access another page per competing store table showing a table of the compared products.

"Bargain" Basket Totals

Tesco, 27 items, 19 unique, £22.99, £25.25, £2.26 cheaper
Sainsburys, 22 items, 16 unique, £17.34, £23.23, £5.89 cheaper
Morrisons, 19 items, 13 unique, £15.62 v £20.13, £4.51 cheaper
Waitrose, 8 items, 6 unique, £10.70, £13.42, £2.72 cheaper

ASDA were more than 10% cheaper for all but Tesco, where they were 9% cheaper. So the voucher covers the other 1%.

Cornish Icecream

But a quick look in the ASDA versus Tesco table shows that some items were much cheaper at Tesco. The very first line is:

1 x ASDA Easy Scoop Cornish Vanilla Ice Cream (2L)    £2.20    £0.99

I though £2.20 was a fairly good price for Cornish icecream but clearly it went in the wrong trolley.

Given that this trolley only resulted in a 27p vouchers, if I had put this item in the other trolley then this trolley would have resulted in no voucher but the other trolley's voucher would have increased by £2.20 - £0.99 = £1.21 i.e., overall I'd have been 94p better off.


I've written a perl script that reads in 4 files in to which I have copied and pasted the comparison tables.

The script is still under development, but here's what it's found so far.

ASDA: (22 compared) cheapest = 16   most expensive = 7
Tesco (19 compared): cheapest = 4   most expensive = 5
Morrisons (13 compared): cheapest = 2   most expensive = 3
Sainsburys (16 compared): cheapest = 0   most expensive = 5
Waitrose (6 compared): cheapest = 0   most expensive = 2

So ASDA is by far most often the cheapest but it is also most often the most expensive.

Getting the items in the correct trolley could make quite a difference.

Other Notes

There are some "errors" in the tables, presumably caused by the mySupermarket website having an older record of the prices than what I actually paid.  For example, we got 8 medium Easter Eggs and they cost £1 each (no linked offers or anything like that). But on the website it says:

3 x Cadbury Creme Egg Medium (178g)    £4.00    £3.00

so this has wrongly resulted in £1.00 being contributed to my voucher.

Also, it was quite nice to have 2 trolleys as they were each lighter and weren't threatening to spill the contents out. It was much easier to repack the trolleys at the end when the items were bagged up.

What's next?

Analyse the "normal" trolley receipt
Work out what the voucher would have been if we'd used only one trolley
Work out various optimal trolley configurations for the shopping
Look in to sourcing the prices before going shopping

v1 script output

Kellogg's Corn Flakes (500g)
asda: 1.00
tesco: 1.98  -- most expensive --
morrisons: 1.98
sainsburys: 1.98
waitrose: 1.98

Cadbury Creme Egg Medium (178g) (3 of)
asda: 4.00
tesco: 3.00  ++ cheapest ++
waitrose: 5.00  -- most expensive --

ASDA Smartprice Sparkling Water (2L) (3 of)
asda: 0.48
tesco: 0.48
morrisons: 0.48
sainsburys: 0.48

Kellogg's Multi-Grain Start (375g)
asda: 1.00
tesco: 2.39  -- most expensive --
sainsburys: 2.39

ASDA Orange Crush Zero (2L)
asda: 0.72
tesco: 0.54  ++ cheapest ++
sainsburys: 0.64

Nestle Caramac Ice Cream Bars (4x50ml)
asda: 1.00
tesco: 1.00
sainsburys: 1.00

Batchelors Super Noodles Chinese Chow Mein Flavour... (5 of)
asda: 2.00
tesco: 2.00
morrisons: 3.45  -- most expensive --
sainsburys: 3.00

ASDA Easy Scoop Cornish Vanilla Ice Cream (2L)
asda: 2.20
tesco: 0.99  ++ cheapest ++
morrisons: 2.20
sainsburys: 1.20
waitrose: 1.30

Mars Skittles Rainbow Pack (4x45g)
asda: 1.00
tesco: 1.40  -- most expensive --
morrisons: 1.00

Kellogg's Honey Loops (375g)
asda: 1.00
tesco: 2.35  -- most expensive --
morrisons: 2.35
sainsburys: 2.35
waitrose: 1.80

Silver Spoon Treat Toffee Sauce (325g)
asda: 0.96
tesco: 0.75
morrisons: 0.49  ++ cheapest ++
sainsburys: 1.00  -- most expensive --

ASDA British Double Cream (600ml)
asda: 1.50
tesco: 1.50
morrisons: 1.84
sainsburys: 1.84
waitrose: 1.85  -- most expensive --

ASDA Smartprice Coco Rice (375g)
asda: 0.65
tesco: 0.65

Dr. Oetker Glimmer Hundreds & Thousands (86g)
asda: 1.00
morrisons: 1.29  -- most expensive --

Silver Spoon Dark Chocolate Chips (100g)
asda: 0.50
tesco: 0.50
sainsburys: 0.74  -- most expensive --

Dr. Oetker Giant Stars (13g)
asda: 1.00
morrisons: 1.29
sainsburys: 1.39  -- most expensive --

ASDA Rich Roast Coffee Granules (200g)
asda: 1.48
tesco: 1.48
morrisons: 1.48
sainsburys: 1.49  -- most expensive --

Nestle Rolo Milk Chocolate Egg with a Rolo Tube (1...
asda: 1.00
tesco: 1.00

Askeys Crackin Chocolate Topping (225g)
asda: 1.00
tesco: 0.75  ++ cheapest ++
sainsburys: 1.00

Silver Spoon White Chocolate Chips (100g)
asda: 0.50
tesco: 0.50
sainsburys: 0.74  -- most expensive --

Dr. Oetker Chocolate Hearts (45g)
asda: 1.00
morrisons: 1.29  -- most expensive --

Kellogg's Variety Pack (8x25g)
asda: 1.00
tesco: 1.99  -- most expensive --
morrisons: 0.99  ++ cheapest ++
sainsburys: 1.99
waitrose: 1.49


Evil Overlord said...

You know that lovely shiny new car you've just got? Well you need to GET OUT MORE in it! ;)

Evil Overlord said...

And NOT just to get more research/shopping either!