There's no need to purchase a potty-training arsenal, but you will need a few items. A potty seat is a must. Some parents prefer the self-contained kid potties, while others (who don't want to clean out those tiny toilets) go straight to a potty seat that fits on top of your regular toilet like the Fisher-Price Perfect Potty Ring ($13). If you plan to potty-train in just one area of your house, you're probably good with one; otherwise, put one in every bathroom your kid will use regularly.
Other necessary items: a stool to help your child get up on the potty if they can't do it on their own, plenty of wipes and cleaning supplies to help with messes, and some nearby books to entertain your child on long potty-sitting sessions.
