I've been looking for an inexpensive helmet for a while and and just ordered a Giro Savant from Backcountry. I haven't tried on this particular Giro, but other models in medium always fit me well. Supposed to be a nice helmet based on online reviews.
Giro Savant Helmet | Backcountry.com
They have some other great deals on bike related items too. I ordered a u-lock (avoid the $5 barrel key ones), 10 speed chain, cassette removal kit, and cable cutter all for about $10 each.
The tools should be a nice upgrade from the cassette lockring tool and towel and Leatherman I have been using.