I don't go to these often, so when I go I tend to buy stuff. I like chatting with the vendors and seeing what they're up to.
I love "upcycled" stuff and if it's something creative I'll often buy it even if I can fairly easily reproduce it myself. I like to encourage that sort of thing and consider it a way to help support artsy/craftsy people in my community.
I like handmade jewelry, especially if there's some kind of local materials used - I have a favorite pair of earrings that are hoops of glass made by slicing rings out of used wine bottle necks and "slumping" them in a kiln to soften the edges. I LOVE those earrings even though they look a little boring...they're "upcycled" AND have local flavor (I live in wine country).
I used to be a soapmaker but I am not anymore - I buy handmade soap at craft shows all the time because I know how much superior it is to grocery store soap bars and it's just too much work to make a single batch of soap for myself. Plus, I like to support the soapmakers! I'm really disappointed when I go to a craft show and there's not a single soaper.
If I'm on vacation and spot a craft show, I like to buy locally-made things as my souvenir for the trip. I look for crafters that are local to wherever I am and usually find some little treasure to take back home.
Right now I'm in the market for a new purse...I'll be hunting around at craft shows looking for a good homemade purse soon. Looking for something unique, creative, functional, and locally-made. I COULD make one myself...but as someone posted from that sign... "when"?? Besides, someone else might come up with a truly brilliant or creative design that I'd never think of on my own. Plus, it'll be a fun hunt!
And sometimes, if I see a booth that is lonely and the crafter is looking low, I will go and try my darndest to find something I want to buy. At the least I'll go strike up a conversation for a bit - I have been on the other side of the table at slow shows and I know how boring and depressing it gets when nobody is visiting your table. I'm particularly outgoing if the crafter is really young and/or I think they might just be starting out. I have even offered a few tips for making their display more interesting, but only when it has seemed welcomed and/or it comes up naturally as we're chatting. (I try not to be THAT lady...) I ended up with a little side work way, actually - we ended up doing a swap where I helped develop her marketing (including fixing up and expanding her website, drawing up a new logo, sourcing cheaper packaging and developing a better booth setup) in exchange for a bunch of her homemade jam. Best swap I ever made, she was super easy to work with and that was some REALLY GOOD jam! LOL
I love crafters, and craft shows.
Neat people, neat stuff. I'm always happy at a craft show.