It depends what you fly in. I've landed at Gloucester and paid £12. I've also paid £57 + VAT!
All landing fees are shown in the Pooleys guide so that's a good place to start.
A couple of points: a free Gloucester landing fee can be had in the Oct Pilot magazine. (valid in Oct only).
A 172 at Gloucester is around £22, £8 last time I visited Compton Abbas and £10 at Bembridge.
Accommodation? Can only recommend at Bembridge. I have stayed at the Windmill Inn, Bembridge and the Sorrento Inn, Ryde. Both very good. For food don't miss the Crab and Lobster. (£5 taxi then walk back to the airport via the coastal path).
Good luck.