I have been in situations where money was tight enough where $3 was a lot: I could come up with it, but there were enough different things that I could apply it to usefully that I didn't want to spend it on something that I didn't know if I'd want once I had it. It was affordable, but too much to throw away.

I also have a bit of a psychological barrier about spending money online, even in small amounts, because I know how small amounts add up if I get enthusiastic about something the way that I know I do; unless I have a strictly defined budget for online entertainment, one that I cannot impulsively go over, I cannot afford to lightly spend money online.

Offline, I control my impulsiveness with careful use of a cash entertainment budget and only using my debit card with deep forethought. Online, I still need to be careful.