You sound like a do-it-yourselfer. When I first got my otter boats I made a mast out of a 6' length of closet rod, through bolted eye hooks in the rod for line storage, bought some planer line, and attached heavy duty deep sea snap swivels. Then all you have to do is find some way to mount it in your boat. This isn't the most high tech solution in the world but it will work and only cost you about $25.
Only other idea I have for you is keep an eye out on craigslist. Sometimes I see them for $75-$100.
Hi, For a mast I just got a piece of steal tubing, and 4 small sailboat cleats and screwed them into the tubing, 2 on each side maybe a foot and a half apart and I just wind the line around the cleats. Works like a charm been using that for years. Yea I'm a cheapskate. he he..