Not really that unreasonable, but maybe a bit high. I'd be more than willing to bet that if you down-scope your feature set by 10%, you'd cut development costs by 50%. What exactly are you building?
Reading up on it, I'm starting to think it should be around 15-25k. It's a simple app which involves payment systems, GPS and talking to 1 or 2 APIs, with a very simple FE.
Without disclosing anything proprietary, I challenge you to describe your "MVP in Three". In other words, what are the three most important value-creating activities your app will facilitate?
Reduce inefficiencies in waiting times on C2B sales through GPS tracking (pretty hard to explain without mentioning the domain).
Not quite what I was looking for, but I'll take it. How's the development hunt going?