If I was playing 50NL now and wanted to spend $50 to improve my game, I'd join cardrunners.com and look at their videos, the main focus of the site is 6 max games, and if you pay attention you will improve your game a lot. I joined the site like 2-3 months ago when I was playing 100NL, now I play 600NL, not all thanks to the site of course, but it has certainly helped me. Having someone look at your game is certainly a good idea too, but I'd say watching such videos would help you more than just a session or two with someone watching. Also if you start hanging in irc or vent I'm sure someone wouldn't mind watching you for a little bit anyways.