Can i connect my iphone 4s to virgin

So I got my iphone 4s unlocked and I'm wondering if I can connect it to virgin mobile and if so how? Do i have to buy the sim off of them?

Assuming you're talking about VIRGIN MOBILE USA in the UNITED STATES - NO! The only phones allowed on Virgin Mobile USA's network are Virgin Mobile USA phones. Virgin Mobile USA does have the iPhone 4S for $387 with current sale price.