Even with the information you gave us, it's a very vague question. You can do alot of things with 5k and a 10x10 room. You could do everything from growing one gigantic plant, to a production of hundreds of plants. Regardless, I think it would be better to read up on some of the threads of what other people have done. Get a feel for what CAN be done and then decide what you WANT to do. but generally speaking, do you own your house? How much time are you willing to spend setting the grow up? How much time are you willing to use to maintain the grow per day? How much growing experience do you have? How high tech are you wanting to go?
The simplest thing I can offer for you is to get some good seeds, a pot, a bag of soil, and a 1,000 watt HPS light, hook all of it up and grow like 10 plants or something. From there, if that is enough, stick with that. If you want more, double the plants. Tired of soil, then go hydro. Want to try something new, buy an omega or try a vertical grow. Repeat the process untill you are recieving the return that you would like, you spent as much as you are willing to, or you are spending as much time as you are willing to. The possibilities are endless and it really just depends on the individual.