I have my first application dedicated to Chiropractor's in the iOS App Store and it's a free download with a monthly investment for half the functionality. I want to offer a trial to show the value, is that possible?
You can't offer trials or even easily make refunds accessible via in-app purchases. What you can do is actually make manual deposits or write checks back to the users who ask for it. But the purchase behavior associated with in-app purchases really shouldn't require any promise of a refund. In fact, doing so might make people *less* likely to purchase being that you're telegraphing a weak offering.
Happy to talk through alternate ways of testing pricing and willingness to pay in a call.
You can add a license component to the app that checks your server for validity when it launches (there are actually services that do this for you if you don't know how to). This way you can offer trials of varying lengths and leave the in-app stuff to for purchasing. I've done this set up with my previous company and it worked exceptionally well.
No, iOS app store doesn't suggest any options for running trials. You could provide another half of functionality as an in-app purchase (freemium)