When looking to find a place an affordable destination to get married I went to Apple.com picked a few hotels and destinations and put in a few different dates and times. For example, I picked the Dream Tulum resort in Riviera Maya because of the 10 mock up trips I faked booked through Apple it was the least expensive. With roundtrip air, 7 nights, and taxes it came to 1447.00/pp.
Hope this helps.