There's something about the phrase "get one free" that's hard to resist. Sometimes, these offers can be a great deal. Buy one, get one free promotions are fantastic -- you're essentially getting two products for 50 percent off. Buy two, get one offers are still good, but not as great, as now you're just dealing with just a 33 percent savings. Buy three, get one deals save you a reasonable 25 percent, and anything over that isn't worth bothering with.
Besides the rapidly diminishing savings, you'll be saddled with multiple versions of the same product. That's fine for something you know you'll use, like diapers (good luck finding a buy one, get one free deal on those), but how many jars of salsa do you really need? Buy 10 of those and earn a "free" jar that equates to 9 percent total savings, and you've stocked a cupboard full of salsa you're never going to use. Congratulations!