Welcome, I envy your dream, many teenagers don't know what they want let alone take action to try to follow it.
As tight as your budget may be in what is a strong market currently, things can turn up or turn around and the bubble burst. It's just that a bunch of self obsessed investors have gotten on board recently and they will constantly talk up their investment.
The best deals come by word of mouth, so you are right to put out lots of feelers. Trawl Craigslist and lesser sites regularly for those elusive barn finds etc. that need to be acted on right away. You might be able to pick up a partial car initially with parts missing that you can build and add to as time and budget allows. Keep steadfast to your dream and keep saving as well and you can make your dream a reality at some point.
Don't listen to the negative comments of the few, they have either forgotten when they were 15 (or perhaps never really were) or all the fumes from cleaners that are required to clean all their investment cars have gone to their head. Scratch that they probably have 'people' for that so they can spend more time on all the forums adding true value
Julian