Looking at the size, I'd say their about 30-80 dollars.
But this is retail price in stores, this is not store. Always find a formula you could rely and depend on. As example: It costs you to make them 14.83 dollars (price is example). Just add 10-20 USD for your work and voila! 24.83 or 34.83 (round it up, 29.99$ super sale prce -20% (which is fake) and keep using this method).
Make page in Facebook, as it'll probably grow as fast as possible if they see how fucking damn good you are at this. (sorry for cursing).
+ Compliment
+ Information
+ Estimated price offered: 60$