SSDs have a limited lifespan like almost any electronic device, but for the average user these limitations are too far to be of concern. I think that the last test I read about indicated that the performance of a modern mid-range SSD started to drop after writing and rewriting the equivalent of ten thousand hours of movies. That's way beyond the life expectancy of a mid-range hard drive, where you can never get away from the fact that they have a lot of moving parts.
If you want to buy an SSD, you should remember that even the cheapest, tiniest SSD has maybe a five-fold performance increase over the hard drive that you already have. Restarting Windows is done faster than you can have a bathroom break, unzipping files doesn't even take a second, and you never have to wait more than three seconds for a program to start.
I bought a 60 GB OCZ Onyx SSD for myself to start with, which was one of the cheapest I could find. I think it's about 1.5 years old now, and I used it for Steam and all of my other games now. There's no noticable performance decrease. When I was running Windows off it, the limited space was really annoying, and I had to pull out every trick in the book to keep from filling it up completely. Now I've got a 120 GB Intel SSD for Windows, and combined with the other 60 GB I don't have to worry so much about limited space any more. The Intel one is supposed to have better performance than the OCZ, but I haven't really noticed any difference.
I'd say there's no reason to buy a high-end SSD if you're not so fanatic that you'll be keeping an eye on its read-write speed at all times, so Intel would be a good choice if you don't want to buy some cheap brand. Also, you always need a traditional hard drive to go with it. Always. Gigabytes are a dime a dozen these days, so get a 1TB hard drive and you won't have to worry about storage space limitations. Tell your parents to install programs on the SSD and save large files on the hard drive. You'll want to keep the SSD as lean as possible.
