which is more expensive???

[jojo2be]

I am wanting to put a small pool/spa combo in my yard in Miami. I received a general quote of $50000 for a concrete pool which i think is way overpriced or is that what i should be budgeting for? I only have a small yard so nothing fancy just something for a quick dip in the hot summers. A friend told me fiberglass was cheaper but then i saw on a website that they cost more than concrete. I am confused!!!! Also if anyone has any recommendations in the miami area i would certainly appreciate it