I use this one, which I picked up on clearance a while ago for about $35. It's a very sturdy stockpot with a sandwiched bottom, which reduces the risk of scorching compared to plain-bottomed stockpots.
If you can use a turkey fryer, I'd consider going for one of those. They usually include a 30-qt aluminum pot and don't cost a whole lot.
The Fiesty(sic) Goat Brewery est. 2007 & Clusterfuggle Experimental Ales est. 2009
Planned: sLambic II, Flanders Red II, Orange Blossom Mead, Fat Man Porter
Primary:sLambic I, Janet's Brown
Secondary: Toasted Caramel Port, Flanders Red
Kegged: Hefeweizen, Centurion Falcon IPA< Dark Saison
2013 dump volume: ~2 gallons