I really don't have any advice, we are not big swimmers, we moved last summer and now have not one, but two neighbors who told us we could use their pool anytime. We used Mrs. F's a few times (maybe 5, & we moved in at the end of June, but I knew this family before that) last summer, but now that Mrs. S. also told us we could come over, we'll probably swim a little more this summer since we have two people that have offered. I was feeling guilty, but another friend said they used to have a pool and it's actually better if it gets used more, stirs up the water and helps with the cleaning, so I'm trying to look at it that way. If I had a friend that had a pool, I would not feel bad about calling and asking to swim. I know if we had a pool, I would want people to come and visit and use it.
I'd probably try and find a cheap pool at Walmart.
Good luck.