I have two sheets from when I moved to my current home and changed bed size, 2009, both are fine, neither is fitted, they're the only two, used in rotation. Both were decent quality but not excessively expensive, M&S and Dunelm. Disadvantage is they're quite hefty, about four times the weight and drying time compared to the cheap fitted sheet on the guest bed.
Replacing elastic shouldn't be difficult, isn't it just in a hem on the corners? As long as it isn't broken, it just needs the end stitching undone and a new piece pulled through by the old. It's a couple of stitches, doesn't even have to be neat, it's hidden anyway.