Mazunte
Mazunte is located in the state of Oaxaca and Huatulco is very similar to, that is the expensive beach town in the state. Mazunte is safe and has several other beaches nearby to explore. The experience you get in Mazunte is as real as Mexican beach vacation get. You should not expect that the big resorts in this part of Mexico, but if you do not need, then you will be happy spending less than $ 10 a day on food and about 20 on lodging.
Barra de Navidad
Flights to Puerto Vallarta not expensive by far, and if you can afford it great, but if you want something a little more affordable then go to Barra de Navidad. The small town of Barra de Navidad is located very close to Puerto Vallarta so the beach is very similar, but the town is so small that you will feel as if you are one of the few in the sand. Barra has a population of 5,000 and is not what you would call a luxury beach holiday, but is still one I will never forget, and especially for those on a tight budget.