You're going to eat up a lot of time AND money travelling anywhere in Asia. You are going to be hard pressed for a flight that is less than $1200. When I flew to China, it was $950, but that was 8 years ago.
You're better off in Central/South America if you don't want insane travel times. I always recommend Costa Rica. I have had a GREAT time there and it is still pretty inexpensive if you don't do an all inclusive tour. The Caribbean coast is less touristed and cheaper. The Osa peninsula is GORGEOUS, but you have to fly into it with a local flight. You can't drive in. The best Costa Rica trip I took, I went to Monteverde, Arenal and then the North Pacific coast. All different and all gorgeous. The most expensive place I stayed was $40/night and that was in Arenal.
I've heard that Belize is really nice as well, and you could get something all inclusive quite cheaply. I'm going to Venezuela in two weeks (Mochima National Park and Isla de Margarita), and I'll let you know how that is.
Here is Costa Rica:
Ahem, why Asia and not Africa, hmmmmmmmmmm?

But I bet you knew I was going to say that. I firmly believe that if you really want to visit paradise and you don't want to spend a lot of money once you are there and you don't mind flying a long ways, Lamu in Kenya or Zanzibar in Tanzania is really the way to go. Cheap, cheap, cheap, delicious food, gorgeous scenery, great diving, and some of the nicest people I have ever met.

It's about $1600 to Dar es Salaam, plus another $100 round trip to Zanzibar but once you are there the cost in minimal. The place I stayed in Zanzibar was $60/night, only 5km from Stone Town (the main port) with a 5 star restaurant and private beach. If you wanted something more isolated, you could get local transport further away from the port and the prices actually go DOWN.
Here is Zanzibar:
If you wanted to go to Africa but the idea of Tanzania scares you, you could try Cape Town, which is also beautiful and it's what I like to call "Africa Lite".

And you've seen my pictures of Cape Town, I think, so I'll spare you the eye candy.