Buying a ploy now, and waiting, isn't a bad idea, but I don't see any benefit. If you're worried about prices going up, don't. Prices fluctuate wildly and are based on whimsey and chance.
Your best bet is to rent, then rent some more, until you find the perfect little gem that you just have to have.
I rented for three years, back in the US for two, and then I will be returning next fall. I will again rent. My plan is to eventually buy some acres between Sosua and Santiago somewhere and build something. But, then again, I may just rent forever.
If you're only reason for buying is for equity, then you shouldn't buy.