If you guys do go for an intex or bestway steel framed pool, dont bother with the ground sheet. It is just a round tarp. You could do much better with old carpet, a huge tarp or, if somebody has some, some kingspan/celotex/polystyrene
I have got the solar cover for mine though. To be fair it is just a round sheet of very heavy duty bubblewrap that floats on the water but it is surprisingly effective at trapping the suns heat in the water during the day