Concrete pad estimate?

You will want to make your pad larger than the pool. You need to have a perimeter footer poured with the pad, and this should extend below the frost line in your area. You'll want to use a minimum of 3000# concrete for the slab, and put in #4 rebar in the slab at 12" on center, tied into rebar in the footer. Assuming the place you are setting the slab is fairly level, they still need to excavate approximately 12" of soil and compact the sub base, then add another 6" of base and compact. I'd estimate labor for this at $7-9K, and materials to run about $2K.