That's mostly what I do, too. I sell them for just over the cost of the yarn, so I can buy more!Normally I pay about $15/20 per pair for yarn, and I sell them for about $20- 30 and then if I can get a bonus of fingerless gloves I sell them for about $10-15.
When I give a pair of socks to someone, I make sure they are "worthy" and will appreciate them. Like, I didn't give a pair to my kids until I knew they wouldn't walk around outside barefoot in them and stuff.
Okay I'm going to start a new thread on sock knitting once I get back from the store.