I was buying some stuff tonight at roadrunnersports.com (new socks, compression top for a base layer this winter, etc.) and it occurred to me to do a websearch for "roadrunnersports.com discount code" and sure enough I found one for 15% off my entire purchase, which already had free shipping! Woot!
It was at http://www.ableshoppers.com/coupons.shtml
I had to type in a couple listed before I found one that worked.
But I'll try the same thing with other online stores in the future, definitely!