I am interested in drawing on my pc with a tablet. Are there any free programs that do what photoshop does for sketching/drawing? If not are there any cheap ones?

Example:
http://www.youtube.com/watch?v=ZeARS4cofRE

Could someone recommend me a decent tablet in the 40-50 dollar range?

http://www.krita.org/ and http://inkscape.org/ And I'd bet GIMP and Paint.NET would do dandy too.

Also, I can't think of a good tablet for that cheap. Most digitizer pens are more expensive than that...

You're going to want to spend more in the $80-100 range for a tablet, unless you want to gamble on monoprice ones. They are of inconsistent quality, but very cheap, and when you get a good one, it's very good.

http://www.monoprice.com/products/subdepartment.asp?c_id=108&cp_id=10841