When you say "secondary membership", are you referring to a second s2Member account (scenario #1) or are you selling membership to something outside of s2Member and just need existing members to pay something extra (scenario #2)?
Scenario #1: This would require some custom coding on your end, as there is no way for s2Member to create a second s2Member account while the first account is logged in.
What I would do in this scenario for simplicity-sake is to show logged in members a link to purchase the secondary membership. The link would automatically logout the member, and then redirect him to a page with a special "secret key" in the URL.
The page with the secondary membership purchase button would check if that access is is correct and only display the purchase button if it is. That way, non-members wouldn't be able to access that page because they wouldn't know that secret access key.
Scenario #2: If you just need people to be able to pay full price ($150) + the discounted price for an additional thing ($100), then you can do that by requiring that members are logged in to see the secondary membership purchase button. I'd recommend using Custom Capabilities (http://www.s2member.com/custom-capabilities-video/) to indicate which members have purchased the secondary membership.
To "sell" this secondary membership to current members (i.e., members who have already paid $150 for their account), you'd use a PayPal Capability (Buy Now) Button to "sell" the custom capability that indicates they have a secondary membership. To prevent people who haven't purchased the primary membership from purchasing the secondary membership, you simply show the Capability Buy Now button on page that is protected by s2Member (so only logged in users can see it).Statistics: Posted by Raam Dev — February 2nd, 2012, 6:25 pm
]]>