Paypal button label or url help

Ok So i am trying to set up Memberships 2 Pro and i have created my different memberships i have i think 7 different paid memberships and 2 free ones. When i go into the settings tab and click on the payments tab the is an area under "Paypal Standard Gateway" the asks for the "payment button label or URL" I have contacted Paypal support and according to them i have to put an amount associated with the buy now button but there is only one url in the settings tab on the plugin and i have 7 different options for the memberships so what do i do because as of now there is no way to actually pay for the memberships they are active but i have no buttons to click on to pay. please assist me with this issue thanks