Ah, so there’s a money/transportation problem. That can be pretty tough. But I’ve been there, too.
– Check out the library for any MA books or videos. That’s your first step.
– Is there a college within biking distance? There’s almost always a martial arts club run by the students, and some clubs allow high-schoolers to join. The membership fee can be really cheap (my judo club in college charged $5 a semester). Most colleges offer some type of self-defense classes; check out the college paper and its website.
– keep up your training. Stay in shape so that when you get the opportunity to train MA you’ll be ready to go all out.
In the meantime, I can give you pointers on riding horse stance (ma bu, say ping ma, whatever else folks call it).
Spread your legs to about one and 1/2 shoulder width. Bend your knees (like Kung Lek says: lower!).
Put your arms out front in a “prayer” position (like a monk; palms pressed together, arms rounded and shoulder level). Look straight ahead, not up or down. STAY RELAXED. (but not “floppy”)
Keep your feet flat on the floor, toes pointed straight ahead (or just slightly inward). Tuck your butt in. When you bend your knees, try and push them outward. You’ll notice a tendency for your feet to turn outward as you do this; don’t let them. You should feel a nice stretch in your hip and ankle joints but not pain. However your leg muscles will start shakin’ and achin’ in just a few seconds.
Try to hold the stance in one place for 10 long, slow breaths. Concentrate on keeping your butt tucked and your shoulders relaxed.
If your knees start to hurt come up right away. Don’t try to push your stance lower if you feel pain in your joints.
After a couple of months you’ll start feeling more relaxed and your body will start “sinking” lower into the stance.
Do the horse stance at the beginning of your workout, just after a light warmup. 3-5 minutes (or longer) in the stance will get you sweating; then go on and do stretches and work out.
Anyway, this is just my experience and I hope it helps you out.

Sam
Umm … yeahhhhhh … that’s grrrreat … – Lumbergh