And this is an example of a pad I wouldn't trust over hardwoods (sadly, from my beloved Overstock):
The 'recycled' rug pads like this one from Pottery Barn are great, but 8x10's go for around $100 at PB!
I get all my rug pads at TJ Maxx, I always buy the rubber ones because they are softer and springier than the recycled mat-style ones. Oh, and an 8x10 pad is $20 at TJ. Yes, ma'am!
Funny story: Before I was a savvy homeowner, I actually tried to duct-tape a bathroom rug to the linoleum to stop it from sliding. It didn't have the rubber backing, and we would skate across the floor whenever we had to pee. Shaun thought I was the biggest nerd for trying to rig it with tape, and I had to go buy a rubber pad the next day. Oh, the silly things I've done in the past!