I would throw that money into a savings account and then use that money to purchase a car when you capable of having a job.
If you want to continue to be smart with your money. When you're 18, open up a Roth IRA and begin saving for retirement.
Unfortunately people are still going to buy this keyboard and that is where true innovation is killed. When consumers settle for less instead of voting with their wallet.
It would never take off with current technology. Modularity is fine in something like a big PC where space is a non-issue but something like a smartphone where space is precious requires precision and optimization.
I'm still waiting on technology that will allow us to charge devices without having to put the device on a pad. I'm pretty sure physics is in the way of that one but one can hope.
I was about to jump on the Apple hate bandwagon but this makes a lot of sense. There comes a point where tech gets so advanced and miniaturized that its actually better that its not user serviceable as to prevent further damage or even injury.
From my short time as an audiophile I remember seeing people spend thousands on quality tubes to pair with their headphones. They would even have certain tubes with certain headphones so that they complemented or enhanced each other's characteristics. Not sure the merits of tubes vs solid state but it seems as though the connoisseurs still like their tubes.