Hammocks come in all prices because they come in many sizes, string counts, and materials. Personally, I have always used cotton-string hammocks. If you take care not to nap in them with clothes that have buttons and don't snag the strings and make a hole, they will last for twenty years or more (of course, that is not with sleeping in them every night). Today, those cotton ones are hard to find; most hammock weavers use synthetic string now. Long ago, you could still find henequin hammocks, but I haven't seen one of those for ages. Those will last forever, but they are not as soft as the cotton ones.
The sizes are tricky. They come in "doble matrimonial," "matrimonial," "individual," "grande," "mediano," and "chico." I always use the doble matrimonial; you can sleep in it and wrap the excess around you like a blanket. The string count is really important. You will not find a hammock for sale on the island at a store that has a decent string count. A high-quality hammock should have a brazo (the strings looped through the woven part that ends in a loop) with over 200 strings gathered at the ear (oreja). The crap hammocks they sell to tourists in Cozumel might have 80. To really relax on a hammock, you need to lay on it at a diagonal, and if the string count is too low, that is hard to do.
There are several guys in town who make and repair hammocks. They can make one to order, in the string count, size, and material you want.
To wash it, tie strips of cloth around the stretched-out hammock and just put it in the washing machine. Hang to dry (do not use a dryer!)
Incredibly, Cozumel is now importing "Yucatan" hammocks from China to sell to tourists, just like the lace tablecloths and sweaters they swear are handmade.