2G will get you a mono-shock (later model) dirtbike, and a helmet, and that's about it.
It will also get you a very fast, clapped out death trap. When Bryan and I bought the Husky 610 ($1500), dude even took the Scotts steering damper off it - seriously. And then we went and bought a cheap helmet, high-quality lock and a jacket for another like 400.
You're gonna need it inspected for chain & sprocket wear and alignment. A good mechanic will check for compression and leakdown in the cylinder.
Bikes ain't cheap dude. Seriously, buy a dirt bike and spend a year ripping around the fire roads and climbing hills. Then save some money and start learning about what you want.
I had a friend that had no bike experience and bought himself a CBR600. And he liked to drink a lot and eat so he brewed his own beer and had a lot of parties and lots of food.
He took my advice and went to Sonoma and took some track classes, and got good enough to see just how much skill it takes to be really slow on a track and how fast race tires wear out, but he bought some gear and learned a few things. So he got a good job and got married and bought a house; so between the beer and the good food. So within about 2 years a 15yo on a BMX bike was faster than him on his 05CBR60RR cos by this point he was like 250lbs, riding a fucking 600 with about a year of skill and drunk everyday.
He decided he didn't want to be my friend anymore (after 10 years), cos of some girl shit and he was too much of a pussy to talk about what's on his mind. So anyway, long story short, get something you'll grow into. Buying a clapped out beater really isn't a good idea, bikes depreciate FAST, they ain't cheap by a longshot. For all you know it's really cheap for a reason. There's very little room for error on a bike.
Check out a DRZ400 or a Husqvrna SM510, If you've never ridden a dirt bike, you don't need more than one cylinder.
So I'll shut up now, and I don't mean to preach; but seriously, learn to ride, take classes, get some hours in, then you'll know what you want.
cheers bro, and be safe