Since I live in Korea, I don't do any thrift shopping of the variety one might back home. In Canada, my mom is a Value Village fiend and I occasionally score as the result of stuff she gets - my coffee is made in a French Press she got ages ago and I carted over in my suitcase on my last trip home and she once bought me a ton of black trousers when I couldn't find any here in a couple of sizes, just to see if anything would fit.
However, Korea is all about the thrifting in a totally different way - first off, we all dumpster dive here. When people throw out couches in particular, someone is bound to come on over and take it long before the garbagefolks could ever get around to lifting it. My friend Vanessa once found a throne (likely from a wedding hall) which she had in her apartment for a year and another friend, Pam, had a cardboard cutout of a Korean pop star of some sort and a sombrero that she found on the street.
The main form of thrifting I partake in here is when someone leaves and gets rid of all their stuff, which seems to regularly include a lot of random beauty products. Hence the toothpaste reference in the title - I hate the tube I'm using right now (Arm and Hammer - yuck!), but I can not in good conscience waste resources and buy different toothpaste when I have a perfectly adequate tube here. I also own enough moisturizer of various types to last me an entire year.
I love used books. It's not just the cheaper prices, though hallelujah, but I also like the whole experience. I like digging around to find interesting books and I aesthetically prefer some older books - especially old Penguin ones. A used bookstore is not a place I can allow myself to visit often though, as I have no willpower whatsoever. Interestingly the book buying ban is going alright though - I cheated a tiny bit by buying two books recently but since they were only a dollar each, I don't feel too bad.
I don't so much thrift for environmental reasons - in fact, I am a rather shitty environmentalist here in Korea in terms of actions. I live a fairly environmentally friendly day-to-day life, but not on purpose. Mostly I don't like the wasting of my resources - something finally clicked for me about how many hours of my time went into earning the money it takes to buy some shampoo and while I will happily spend what used to be half of my montly budget back in university in a single night in a bar these days, it annoys me to spend my hard earned won on toothpaste and moisturizer. I don't really get why, but there it is.