I can suggest my broker, FP Markets. I trade with their ecn raw account that offers some of the lowest commission costs among other brokers, and the spreads are tighter, which is an advantage for me since I'm a scalper.
You can give turnkey forex or eaglefx a try, commission is $2/lot and $6/lot round turn respectively. Spreads also remain tight, overall good conditions.
Hotforex charges 4$ round-turn commission, heard that is the lowest but I guess many brokers charge this amount. What you should pay attention to is slippage and tightness of spreads, unfortunately unless you try it by hands there is no way to figure out how good is the broker in this regard.
I am currently trading with an FP Markets Raw (ECN) account. Their trading conditions are extremely competitive and they have some of the best spreads out there, I recommend trying it and experiencing their ECN pricing at least once.