http://www.sierratradingpost.com/sea...s=True&page=10
Here's 372 results from a 'merino' search at Sierra Trading Post. Lots of socks.... I didn't scour the results for screaming deals, but I've gotten bargains on lots of stuff from this company. Great customer service.
+1 on thrift stores. I've picked up some nice sweaters for a couple dollars.