Hey Shaggykid, don't let not having a car bother you, whether you're 16 years old, 18 years old, 22 years old, or 25 years old. I'm not THAT much older than you are (assuming you're closer to the latter numbers) and I have, at the moment, four cars, but in the past two years that number has ranged from 1 to 6 (I race and modify BMW's, as a hobby and a stress-reliever).
But, I also have three bicycles:
Fuji Tahoe 1.0 (Off-Road/On-Road "Fun" Bike) - upgraded wheels, tires, brakes, chain, derailleur, etc
Redline Conquest Carbon Team, factory customized (Training Bike) - full carbon frame; upgraded all components to Shimano Dura-Ace/Ultegra components
Fuji Altamira 1.0 DI2 DA Carbon (RACE Bike) - 100% carbon fiber ultra-light bike; upgraded only brakes, brake lines, shifter lines, seat, and tires
Sorry, wasn't my intention to go off topic.
Anyway, I applaud you for getting off your ass and actually biking 10 miles to a store, and another 10 miles back! That's quite a bit of exercise, and the country could use a lot more people getting on their bicycles instead of their cars, especially for the really short trips (10 miles isn't a short trip, though!).
Keep working and saving for your car, that's what I did when I was in high school... 40hr work weeks for three and a half years in order to buy my first BMW, which I still have to this day and is now my track monster
Just to keep my post somewhat on topic....
YAY NEXUS!