suggestions? pontoon boat aluminum frame

Looking for suggestions from anyone about different makers of pontoon boats for fly fishing.. and retails sales location here in Western Washington.
I am only interested in aluminum frame.. and under 500.00
So far my best bet seems to be Cabela's thanks, Ron on The Willapa , WA. State
Bucks Bags Southfork is the best pontoon at 600.00 and under but the frame is Stainless steel, which is superior over aluminum if the diameters of the frame tubes are the same. In other words, a 1 1/2" diam thin wall alum frame is stronger than a 1" diam wall SS frame.

Good luck!
do you do mostly lakes, or rivers? for lakes there are a number of cheaper pontoons that are fine, but you might want to go with something a bit tougher if you fish rivers that have much flow. a southfork weighs 65 lbs and is pretty easy to handle. ebay often has really good deals on pontoons of all brands.