Hi Sintelligent,
The script I use is autogallery sql from JMB. It's not the most feature rich but, in truth, it does everything you could ever want and it's only 85 bucks.
http://www.jmbsoft.com/
Most of the info GG generously gave you can only be found by getting your hands dirty and searching it out piece by piece.
Here's what I'd do in your position - assuming tgp is truly what you want to do.
1. Decide on your niche, how you want to brand it, and the name you'll use.
2. Get your domain name.
3. Find a good designer and get it built for you from the ground up (script included). Tell the designers you want a trade script installed as well.
4. Buy some traffic from here :
http://www.traffic-out.com/ to kick start your site.
5. Work on trading with other sites - and buy more traffic if needed.
6. Submitt galleries and use your own recip as one of the 3 you use.
7. Pay for traffic at different places and use your tgp as the upsell. 300 bucks will get you on sublimedirectory and 500 will get you on the hun (although he's booked for next few months).
If you need any specific help, just email me. I'm not looking for a job, just being friendly
webmaster at fuk18 dot com