Replacing a liner

We got 8 seasons out of our original cheap AGP liner. Which is great considering we got a gaping hole in it a week after installation! This year we pulled the cover off and saw that we had only 2-3 feet of water left and the liner was pulling apart from the top. (It had actually begun this last season but was minor.) So I've removed the old liner, repaired a bunch of surface rust on the walls, filled in sand washouts, ordered replacement caps and am preparing to get more sand to re-level. After reading the various posts on using coves, I've decided to get a vapor barrier and tape to the walls making an L with the bottom and building the cove with sand to prevent the problems of the past. Browsing the aisles at The Home Depot (R), I found various thickness painter's plastic. Is there a cheaper vapor barrier? Also, what kind of tape would you recommend?

Thanks in advance for your help!!

vapor barrier is 6 mil, it's heavy enough, I found most painter drop sheets to be very flimsy in guage, closer to saran wrap than plastic sheet.
I believe you can get rolls of 2' wide vapor barrier (possibly black) for underneath/wrapping your 2x4 plates that touch the concrete floor, they may be cheaper than buying an entire roll of 6 mil vap barrier.
I think even a tarp cut into strips would work, as long as you have something that's a bit substantial it should do the trick.