Sam, Monarchs only use milkweed as a host plant, there are different types of milkweed tho.
A female will lay 1 eggs each time she lands on a milkweed leaf. I would not rush into this because so much could go wrong and you may end up hurting the species instead of helping.... that being said.. the link I provided will help you along on your search for knowledge.

Here is a link that might be useful: Monarch Watch

No Sam, they don't. They only use milkweed. I just attended a lecture on Monarchs, and the presenter said that they use about 25 different Milkweeds in North America. Females can lay up to 300 eggs. There is so much information about Monarchs on the internet. You might check out www.monarchwatch.org for tons of info. Raising them is easy. You just plant the milkweed, wait for a female to come and lay eggs, gather the eggs and caterpillars, and then put them into a container where they are safe from predators. You keep the container clean and dry, and you keep fresh milkweed in for the caterpillars to eat. The caterpillars eat and molt, and after they have gone through the last molt, they will eventually stop eating, attach to something, and pupate.
Angie

Thank you everyone. Very helpful... Maybe I will wait a
While to raise monarchs :)

Start with 1. Once you get through your first, you'll be hooked.

When they're small, everything is so simple. When they get big, they eat a lot. And just when you think you have enough food for them, they'll either devour it all or go off to pupate, something that happens constantly for me.

If you don't have any milkweed, there are plenty of people in this forum alone that will gladly send you seed, myself included. When something unexpected happens, you post here and you'll get the best help you'll ever need.