The first rule is buy japanese preferably to start with. If it doesn't say Honda, Yamaha, Kawasaki on it, pass. There are a million and one names on the market all coming out of china at prices that are very attractive. They are cheap for a reason, and unless you can fix anything that might happen by yourself just pass on them. They're going to tempt you, you may not listen, but I'll say in advance that I told you so. Something will break before you have a chance to resell it, and it will cost you more and more and more. Something will break every month.
Or you can get a Vespa or other legitimate quality name that's from other countries too, provided there is a service center for them in your area.
For the record I own two chinese bikes and I'm ok with them personally and am not saying any of this out of a grudge. I got them under dealer cost, a LOT under, I baby the hell out of them, and I can fix pretty much anything myself so for me it wasn't scary to try them. I wish I had bought a single 30 year old japanese bike, a real bike though.
Nothing but problems so far, and both are under 100 miles on the odometer.
Which model bike to get, I would say go with something USED, that is very common like a ninja 500 or some common jap scoot. (the ninja 500 is not a race bike, it only looks like one but it has just enough power to get on the freeway and not be run over. A 250 isn't enough to ever get on the freeway much really and that limits their resale value and appeal.) If you don't know road riding is for you, then you want something that will not break down easily and will be sure to sell quick and easy for exactly what you paid or at least close. That's a ninja 500 you find a good used price.
Some scooters are quite popular and hold value well even if they are less or much less and can't surpass 35, 45, 55mph. But they don't sell and resell so easy all the time.
I'm not familiar enough with scoots to give a specific model if you want a scooter more than the ninja... I defer to others on that one.
Take someone with you who knows bikes inside and out or have it checked out at a dealer before handing over cash. Don't buy brand new unless you want to throw $1000 away or more, try to stick to recent model or super well kept models under 10 years old.
When I said I wish I'd bought a 30 year old jap bike it's because even at 30 years old they are still more reliable than the chinese stuff new.
