Nifty! I like your style.
I didn't buy any art this year due to budget concerns (and the concern of getting them from convention to home without wrinkling). I'm super thrifty, always looking for decent quality goodies at affordable prices. At the artist's alley, there was a wide spectrum in pricing, even in prints.
I would encourage you to add on a bit for the costs of laminating them, the supplies, and the amount of time/effort you put into each one. There needs to be an equal "energy exchange" -- if you put $50 worth of work into something and only get paid $5, you might find yourself feeling yucky and resentful and kicking yourself later. Be honest with yourself.
I was both a con-goer and quasi-vendor, this year; I kept my chair massages affordable for a length of time that felt proportionate -- $5 for ~10 minutes. (At my day job, I offer 30 minute table massages for $20, just to give you an idea.) There was one customer who wanted 20 minutes of chair massage for the same $5, and I didn't feel so great about that one. There were a handful of people who didn't pay at all (not even an interpretive dance!), but the people who tipped generously and sent their friends my way more than made up for it and I left feeling really good about the convention.
So, in short, pricing can be really subjective. Polling people, like you did here, is a good thing. You deserve to get paid for the work that you do, especially if you want to make a side-job or career out of it.