Vintage Fabric Aprons: costing: HELP WANTED

I need your help costing my aprons!!

One of our ongoing assignments in my Fashion Design & Technology course has been a market product project. The theme is 'the Circus' and we had to come up with a product, produce at least two and then the classes will be holding a stall at a well known artists market in December.

My product has been a bunch of aprons, I've ended up with 8 in total because I expected to have a few failures. It's taken all term to produce these because along the way we've had to do inspiration boards, presentations, costings, quality control testing etc etc. 

Yes that's my Horrockeses dress on the dummy.

I can't believe how long an apron takes to make with all the testing, working out how long, how long for the ties, how big for the pocket, pocket position, how much gathering, how far around the body, on the waist? on the hip?? and on and on. 

I have only two finished so far. On the remainder the only thing left to do is to the bias binding along the bottom edge of the ties, fiddly but pretty easy really (since I discovered I love doing bias binding). 

This pink stripe apron is not made from vintage.

 

Now the last step is to work out how much to charge at the market. Very hard to calculate since I've spent hours on them. 

So what do you think?? 

What would you pay or expect to pay or what do you charge for similar. 

I'd love your help.

These are the unfinished lot.