Okay I gave a 2010 mustang GT manual 5.0LT V8 it have a custom paint job(mustang boss 302 paint job) baby blue with the black 302 stripes and hood. Back up camra and light up cup holders. What should I trade it for?
First off the 2010 GT had a 4.6 NOT the new 5.0. Check KBB for value but remember that the custom paint and hood actually LOWER the value of the car. It sounds backwards but it's true. As far as what you should get it depends on what kind o car you need or want. Do you like the mustang but want something with better MPG? Look at a 2011 or 2012 Mustang V6. 300HP and 31 mpg.
Need a truck? the new F-150 or new hemi dodge rams are all fine options, and the rams have some VERY nice interiors (specially for it being a truck)
Learn what you actually have before you even attempt to trade it. A 2010 Mustang GT doesn't have the 5.0. Do you owe anything on it? If you do then it's probably not a good idea to trade it in on anything until it's paid off. Even if it is paid off, the dealer is going to have a field day with you based on the lack of basic knowledge of your own car you've displayed here.
Pro Tip: Bring a friend who knows more about cars than you do with you.