If money is an issue, I'd stay away from Sandal's. They are nice because they pretty much guarantee a minimum quality, but they are a little expensive. If you do your homework, you can get close in quality for much less (like 1/2 the nightly rate price).
The cheapest options I've seen have all been on the eastern shore of Mexico. Haven't actually done those because the reviews of those places were all hit or miss. Out of the islands, the cheapest place I've been able to do is Punta Cana. If you mainly want to lie around the beach and drink, it's a great option. Not much else to do though if you're looking for excursions or to do good scuba or snorkeling.
Since it's your honey moon though, if you can afford Sandals and you can't get a good recommendation for a cheaper route from somebody you trust (that has been there in the last 12-18 months), I'd go with a Sandals.