Technically you can use any two drives for RAID 0, they don't even have to be the same size.
The problem is with different drives the performance, and firmware on the drives don't always work together as well as they should, and if the drives are different sizes you can only use the space of the smallest drive.
I always say buy two drives that are the same, at the cost of drives these days that isn't usually a problem... BUT if you do decide to add a second drive which is different to the first it will work.
Oh and nearly every mainstream motherboard made in the past 6 years has an onboard RAID controller so that shouldn't be an issue for you.