I want this GZ but will it be too much trouble?
 

Im looking to get a gz250 without a lot of cash. Someone is selling a 2007 gz250 with 30k miles. But it has trouble. Per his description "starts and rides great but dies when ridden on the freeway- loses power and then dies like its running out of gas buddy said it may be venting issue on gas tank or fuel line kinking or carb float valve. pull over and it restarts fine ride for another mile and it does the same thing".
I dont mind learning to fix it, but do you guys think its going to be too much trouble? Any thoughts on what the trouble could be? He wants $800. Thoughts? This would be my first bike.

Sounds like a bike that needs some TLC by a new owner. The issues you have mentioned are a simple fix in most cases. Starting with a bike that needs TLC is a good way to learn about the bike and hone your wrenching skills on the minor stuff. Assuming the bike hasn't been bent or treated real bad you may have a diamond in the rough.
We have a wealth of knowledge and experience here and are more than willing to share.

Curious did you buy it?
Symptoms could be as simple as a long overdue valve adjustment.

...or a leaky vacuum tube.

Yeah, these things are pretty easy to work on and there are a lot of people on this forum know can walk you through most repairs/fixes.