Please specify what type of guitar this beginner model is. (Electric, steel-stringed acoustic, classical, other) If you know the exact make and model, then post that also.
If it\'s an electric, then you probably won\'t go wrong buying a beginner model to save money. As long as the body and neck are full scale, there shouldn\'t be a problem.
Having said that, there are other problems that might be present, as CHIZZY said. You have to inspect the guitar to make sure the neck is not warped, or you could experience weird buzzing that will be very hard to correct. If the neck is ok, and there are no cracks in the neck/body joint, there should be no other problems that cannot be corrected with relatively simple repairs. Even cheapo guitars can be set up properly with correct action and string tension.
It\'s just a matter of personal preference. The big danger is that if you\'re a beginner on the guitar, you might not be aware that there is a problem, so you might continue practicing on the guitar, not knowing that it should be repaired somehow. I\'d recommend that if you haven\'t picked up and played an expensive guitar, you should go to a guitar store and try it. You can use that as a baseline to compare the status of the guitar you\'re planning to buy.
BTW, if the guitar is an acoustic of any type, then very little of the above advice applies. Cheap acoustics really do sound cheap, and expensive acoustics really do sound good. There are few bargains in the sound of an acoustic guitar.