I got a 120k BTU burner from Academy (their house brand - "Outdoor Gourmet") for $30. Its quiet, efficient, sturdy, and cheap. Not pretty though.
Also, whatever burner you get, I highly recommend getting a one that has only three legs, not four. With four legs the surface you sit it on needs to be perfectly level else it will rock back and forth. There's no way for a three-legged burner to rock like that.