well firstly it is best to get two pigs. if you keep a pig alone he/she will get lonely. they are social animals and need to interact w/ others of their kind. there isn't much of a difference in taking care of one or two pigs.
and no, they don't smell, as long as their cage is clean.
i have two girls for a year now, and they really grow on you. i love them so much. If you want a pet you can sit with and cuddle then guinea pigs are a good choice.