It depends on who they are for
. I use nice wool yarn for dh and for gifts. For me, I get cotton or a bamboo and get it on sale. I have paid as much as 20 bucks for sock yarn for a pr for dh in wool. But I usually have leftovers, so I put that to good use for smaller projects. I have also knit them for 8 dollars a pr and my cheapest 5.00 with yarn I found on close out.
Granted, not as cheap as Target socks, but like one poster said, they are fun to make and you get a lot of knitting entertainment.