Stag lowers are good to go. I have 1 (used to be topped with a Stag upper too), and I have zero complaints. Every mag I've tried in it drops free and the machining looks great.
That being said, for the most part, a lower is a lower. Pick out a rollmark you like from a reputable company, and you'll have no worries.
A lot of lowers' prices have gone up. So $139 actually isn't bad. Go for it, if you only want to buy local. Otherwise, I recommend Anvil Arms. They are one of the "good guys" who haven't jacked anything up (yet). Their stripped lowers are still going for $100. Plus they offer free laser engraving.
I'm not sure of their inventory at the moment but check 'em out:
http://anvilarms.com/c-19-lower-receivers.aspx .