I'm with Fin59 and orbitz 200entertain code and Cozumel. My wife and I used that code a couple times and got roundtrip air, 7 nights (last time we stayed at Occidental Grand which we love) for $634 per/p and that was all Inclusive. I just checked for April using the same code and found one for Hotel Fontan for $1,018.59 USD total with air for 7 days. Oh, and that's from Kansas City.
If you stay directly in Cozumel at one of the budget hotels you can get it cheaper. My wife and I love nice beaches, which is hard to find in Cozumel unless you get way south. We stayed at Occidental Grand and absolutely loved it. It's way on South end but it's a ways from all the stuff going on in town. For us, we've seen all the shops and things in MX so we just like relaxing, reading, and diving.
But if you want to relax, nice beach, close to diving, this was exactly what we wanted. Nice resort, all-inclusive and literally 5 minutes to most of the dive sites the ops from in town boat out to. I enjoyed the 5 minute boat rides to the diving. Plus we didn't dive every day so having a nice resort style place to stay was nice.