http://www.jmbsoft.com and get Auto Gallery SQL. it's cheap. $85
I don't know much comus , madTGP, or brownie cost, but i think they're all a lot more than that.
Then you can go free trade script.
Turbo Traffic, CJUltra, Arrow Trader, etc.
I don't know of a gallery manager and traffic trading script in one.
That's what i think is the cheapest way.. not necessarily the best way.
hope that gets you started.