Your best bet is to go rent one like I did last year. I pain 15 bucks to use it for a week and that saved me a few hundred on a case! I have to say it freaked out the people checking bagage at the airline!
I went to a local bike shop and they had them in different sizes. They said they keep them because cycling has become so big that everyone wants to take their bike everywhere! The guy at the shop said that this was the way to because I wouldn't be traveling that much. I have to say that I agree with him and it was easier on the wallet.