Guinea pigs are brilliant pets! They will communicate constantly, their range of calls and squeaks are either annoying if you don't like noisy pets, or utterly charming if you like a pet that will learn to call you when it wants feeding!
They need vitamin C in their diet, tomatoes and sweet peppers are a good source for them, and good guinea pig food has pellets containing it.
I've had breeding groups of guineapigs as a teenager and again while my boys were younger. They do best in pairs or groups because they are so sociable. If you're thinking of breeding them, the females have to have their first litter before they are 10 months, otherwise their pelvic bones fuse and would make breeding dangerous for them.