It takes several months to set up a colony, but they are easy to care for. Check out "snails in the mail" and sandrachameleon here on the forum Has a great blog on caring for snails. Keeping them moist is key, so I spray mine almost every day.
I started with 10 snails They are a little pricey (about $6 each with shipping), but well worth it to start a breeding program. They are poop factories, so be warned.
I've had one batch of eggs right off. I've found that they like to lay against something hard they can dig under, so I added a rock that is sunken into the soil. The soil has to be soft and moist, too, so I try to "churn" mine periodically with a fork. Yes, they are a GPIMA but way easier to me than silkworms. Silkies always die on me, and Ferdinand doesn't really like them that much either.