Bargain Hunting

When I go shopping I have a no turning back rule - I won't go back to buy something I've already seen. Either buy it now, or move on and don't come back. The rule is designed to force a decision, and stop over deliberation.

It does raise a bit of a problem though; I'm worried about not getting the best deal. I have just learnt a strategy which copes with this bizarre behaviour. I read about it in The Perfect Swarm by Len Fisher, though he says he got it from Simple Heuristics That Make Us Smart.

When you're shopping for a bargain, and can't go back and choose a previous item:

• Set a maximum number of things to look at.
• Look at the first 7% of items, making a note of the price but not buying.
• Continue browsing, and choose the next thing which has the lowest price so far.
• This heuristic gives a 92% chance of buying an item in the cheapest 25%.

If you have more stamina, look at the first 14% then choose the next one with the lowest price so far. This gives an 84% chance of buying a item in the cheapest 10%.

I have another rule to protect myself after purchase. The ignorance is bliss rule - after buying something do not look at any more prices. Definitely don't go in any shops selling the same sort of thing, and preferably go straight home. I never take anything back, so it's better not know that a better bargain may exist.