I'd rather get the 2 for 1 or 3 for 2 offer and give one away to a friend or relative...

I may be missing something here, but surely if the price per item (in the 6 pack) is less than the single item price (for the same sized item) then you would know that buying it as part of a pack would be cheaper than buy the single item without needing to resort to a calculator, wouldn't you?

I more often find that someone's forgotten to sense check the special offers, they have labelled the Tesco own brand Assam teabags thusly:

50 bags: Buy 2 for £2.00
100 bags: £1.65

So they're basically saying "buy the same amount as the bigger box, and pay an extra 35p for the priveledge.

Edited to Add: Oh, and I don't have a problem at all with the BOGOF Later plan, I would just put the coupons in my wallet where I can't help but spot them the next time I have to pay, just like I do now with my Tesco Clubcard vouchers.

Tesco are fond of offering 2x2l Coke seperate for £2.50, or you can buy it for £2.75 in really annoying plastic

It's not a failure to sense check, it's deliberate. Or at least that's the allegation being made by the likes of BBC Watchdog. Most people will automatically assume that the special offer must be better value when it isn't. Never underestimate the power of stupidity.

As for what I said in my original post, the point I was trying to make is that they deliberately use a wide variety of differnt units in an attempt to make it harder to work out which is beeter value. Take another example. Two packs of pasta. One 500 g the other 2kg. The will list on in p/100g and th eother in £/kg when it would make far more sense to list both in the same units so the consumer could check quickly which one was the better value. This doesn't happen because it's not in the supermarkets interest to do so because people would be more likley to choose the cheapest verison.
In my original example say they are cans of drink. One will be price/330ml while the other will show price/100ml. It's not that difficult a calculation to do in principle but it's also not as simple as it could be and IMHO this is deliberate.

I agree with the deliberately confusing 'ratios'. I've often found it easier to buy multiple individual items than multipacks from Tesco. Not noticed it in the other supermarkets but TBH I just buy what I want, when I want.

Whatever! I do what I want!