I'm usually on a tight budget, so price is the main factor I have to consider when making purchases. I'm often so hesitant to make purchases even with what seems to be a "cheap" thing because my brain likes to metaphorically beat me up by telling me I should have saved my money for something more important. But then again, if I listened to my brain, I'd be spending no money on hobbies and I'd feel miserable, so...
As for what makes me buy something when it's within my budget, I'd say it has to do with the art and the vibes I get from the story or setting. If I think the story will sound interesting and I like the look of the art, then hell yeah, I'll drop some money on it. If I feel off about something, though, I'll hold off on my money.