Should I charge more than $29 for this sidewalk sign?

I'm getting ready to launch a new website
http://www.tendollarsidewalksigns.com

It's going to sell blank a-frame hardware for $10. I am also going to start carrying a line of pre made designs and was thinking about making them $29. My goal is to get a lot of volume so I can keep my (already paid for equipment) moving at night and generate a 2nd revenue stream.

How much would you pay for a sign like this?

Location: 
United States