Flights are ranging between $300-$500 depending on when you book. We understand this is a lot. Options you can use is booking through Affirm, which would allow you to make payments. We have used Affirm before, so if you have any questions about this option reach out.
We will be staying at The Courtyard by Marriott Isla Verde Beach Resort from the 18-22nd (you are welcomed to come anytime before and leave anytime after the wedding) The price is about $255 a night. There are Hotels and Airbnbs nearby that you can check out that may be a little cheaper. You can also book on hotels.com allowing you to book now and pay later.