Val - when I hung out at the other DR forum, I noticed the same thing. A lot of people there did analyze the price more than the need. I think it takes time to move away from consumerism. Paying off debt is a great step in that direction, because who *really* wants to go back once it's paid off?
I think this forum's title is actually spot on. Simplifying tends to be the priority, but we also discuss thrift in the context of simplifying. That and meeting basic needs. But pretty much all of us have categories where we feel the least expensive choice isn't necessarily the best for whatever reason. Frequently it does boil down to our own morality: don't want to support exploitation of people/animals/the land here in another country, so we buy fair trade, local, fuel efficient or organic. Often, I find that used is an option that suit my needs without creating more demand for resources. That and making do.
I actually shop the thrift store with a list. I don't buy things because they're bargains any more.
I did find that the months of compacting really affected me. I'd like to start again with the new year - the move made it impossible for a while. Some things simply had to be purchased new, but most of what we did was repair/scrounge/buy used even then. Paint wasn't preowned. But the floors were refinished, and the carpet we put in was made of coke bottles.
I haven't gotten a microwave here, because I'm not sure I even need one. But I will say we were out on Black Friday evening trying to replace DH's computer monitor. We ended up doing it another day.