What's the easiest/cheapest way to make my 50cc mini motor faster? ?

Change the front sproket to a bigger one or the rear sprocket to a smaller one

Trade it for a 900cc Harley Davidson.

The cheapest way is to sell it. Put the money from the sale towards something with a larger motor. Your other alternative is to throw lots of money at it for only marginal performance gains. There is no cheap way to get any real power from this tiny engine.

git a bigger motor. (sic.)

There's not much you can do with that, you can put a straight pipe on it, but it will be REALLY loud and you'll only gain the tiniest bit of power.

1. Take it on the bus with you 2. Strap it to the back of a Hayabusa 3. Drop it from a tall building 4. Launch it from a catapult 5. Strap a small rocket to it 6. Pack it in Usain Bolt's fanny pack All these things will result in your motor moving faster than it does now.

If you have a electronic governor you may be able to unplug it and go a bit faster- like 40mph as compared to legal restricted 30mph. If the moter has some other restriction- as exhaust block or throttle stop, then remove them. Exhuast port work on 2 stroke is not advised for beginners, camshaft changeing on 4 stroke may be more expensive than worth it. 50cc motor used for legal reasons as in age for drivers license or beginner size restriction should be left basicly as is- legal hassle if caught with modifications or removved restrictions. Offroad class size usually no power restrictions- do what you can. Maybe better if first year riding on street to keep it stock and save up for 125 if in England for next year. Since you didn't note what state you're in and drivers /vehicle license status, can't give much more than general info.

Sell it and save your money and when your old enough and have enough money ask your mommy and she can help you get a real motorcycle.