I agree with Murray's comments. When you find a folder that you like, contact the maker and just ask some questions. Establishing that initial contact can go a long way towards a good working relationship for both of you.
Your budget will restrict you fairly significantly. I don't mean to speak in regards to your personal finances, but if possible, you might consider saving a few bucks here and there when you can to supplement your budget. Most makers of quality folders are likely to have at least a little bit of a backlog anyway. This would buy you some time to work with a maker, hash out some details and save some more money. Having a larger budget will definitely open up your options.
That said, there are likely a few decent folders out there in your price range. They just might be fewer and farther between.
The type of folder you are interested in and the materials will play a role in the price of the knife too. If you're not sure what you want there yet, it's all the more reason to look around and decide on what you might be interested in.