Hi, 

we have a skydiving business and we are interested in seeing how much you will charge for an app that gets customers info (from gravity form), enters into a database, adds what cost, what jump location, how many jumpers in their party and all their address details, weight height etc, what deposit they have already paid (paypal) and reminds us to invoice them (with a paypal pay now button) 2 weeks before the jump date. Needs a calendar view with lots of different search facilities. 

The jumpers may choose a chartity so that needs to be in there as well. It also needs report functions. Also needs to have a group email function so generic email templates can be sent to all relevant people in one go just by selecting radio button maybe. 

There a few more things but hopefully you get the idea. Thank you, (in UK)