WE have friend wqho live in Avon year round, so when we go we stay with them (sorry I can't help you about the rental prices).
WE LOVE the OBX. Avon is not as commercial as some of the more northern beaches, which is what we like. It still has shops and such, but less people. You are also close to Hatteras and the Ferry. The Island makes for a great day trip.
We also went ot the aquarium last time we were there, it's small, but a nice day thing.
We love that you can drive your 4WD truck on the beach (no permit!), it makes it so much easier then lugging everything onto the beach, you just load it up in the car!
We are gonig to WDW this year instead of OBX (it was preplanned, then the husband of our friends, was diagnosed ot throat cancer, and while he is finished with his treatments, he is still under the weather), so tlakign about it makes me miss it as well as our friends.