The cost is NOT more expensive and you obviously aren't showing them the prices to prove that. The mac mini is $600 and the iMac is $1000 (education discount is even cheaper). That is not any higher than you would spend on a PC
That's not quite true... in fact, a long way off... what about a Dell with better specs than a Mini for $359?
http://www.dell.com/content/products/features.aspx/dimen_essential?c=us&cs=19&l=en&s=dhs
If money is an issue, it's hard to argue Mac is better value. And as far as "It just works", that can be said of most current PC's too. Maybe Vista will have some driver issues for a while, but then again Tiger wasn't flawless when it came out, and I doubt Leopard will be either.
dominicansrul93, if I were a skeptical parent watching my pennies, I'd be wanting some better reasons for getting a Mac than most suggested here. It sounds a little too much like "I just want it" - which parents hear all the time.
My suggestion is to show your commitment to the Mac by offering to pay the difference yourself. In the above example of Mini vs Dell, the difference is $240 - do you reckon you could come up with that? I guarantee THAT would impress them!
Good luck!
Trevor