Hi- I saw old navy has their sale this weekend too. Michael's has them for $1 and they are actually good quality- kind of squishy. They have black, white, yellow, royal blue and pink (more of a light raspberry color). The store I went to had them in the back and front of the store - so if your colors are MIA, poke around a bit.
There is no limit to how many you can buy and when I went to the register I had 40 pairs and the girl working there asked it I was stocking up for summer. I thought that was cute.
Have fun!