How to Offer Free Membership Trial Without Credit Card???

Hello,

I want to offer a 30 day trial membership to users without them needing to input their credit card info into Paypal. Once the 30 days is up or sometime before, they can then upgrade to a serial paid account or they will be downgraded to a Visitor account, which will block them from most of the site's features.

Is this possible to set up with the Membership plugin. If so, how would I go about doing it?

P.S. We're looking to make our site live in 2 days and this is the main thing we need to complete in order to move forward. So any prompt help will be greatly appreciated.

Thanks!