A bike in the 2-3k range is going to be an older bike or a newer bike thats went down or salvaged. Be careful buying a used bike they can have a lot of problems...I would try to push for them to spend in the 3500-4500 range and grab something more reliable.Better off spending a little extra cash now and not have to spend it in the future which i can guarantee you will....
IF they want to learn, the answer isn't a cheaper older shittier bike.... the answer is to go too a motorcycle safety school......I personally wouldn't buy anything under 04-05 at this point but im sure anything above a 2001 will be fine if the person selling it took care of it. i would try to stay to 1 owner or two owner bikes. Find out why they are selling it and really check the bike.
People get bikes and normally do not take care of them because they are seasonal and only care about them during riding season..obviously when buying an older bike with more than 1-2 owners there are a lot more variables.... Make sure you really feel the person out before you buy the bike and don't rush into buying anything.. If they can only afford 2500-3000 range they should save some extra money...if they cant save more money they probably shouldn't buy a bike.
Try to get something with some service history. Bikes mileage is normally not accurate because its very easy to switch out the odometers.
spending 3500-4500 they will be able to pick up something newer.
Any bike brand should be good for them. Too learn a 600 is great yes, but it's all going to matter on the rider. any 600 can do 140+ and so can a 750 1000 etc...either way they will have to learn the correct way to ride and their throttle control because some bikes are snappier than others......
i own a 07 Suzuki 600, also owned a older honda, and my roomie taught me on his r7. the yamahas are more for the track, they are taller and really for people who want to lean and do turns. for ny and city driving i would say go with the suzuki or honda. all great bikes, just need to feel out the seller and check the bike out thoroughly.
stay away from old ninjas, i think they are garbage.
the older hondas are wheelie machines and normally beat up from being vertical.
old suzuki bikes are very heavy..