1. I have MarketPress setup in the mu-plugins directory so that it is active on each site. I am not sure how I should configure the gateway settings that work best for being able to keep a percentage of sales on all free stores and not for supporter stores. I have PayPal Chained Payments set for All Can Use and PayPal Express Checkout set for Supporter Sites Only. Is that correct?
2. Do you have to sign up for a Paid monthly service with PayPal in order for PayPal Chained Payments to work? I have setup PayPal API Credentials and an Application ID but don’t know if they will work without some type of paid service with PayPal. What do I need?
3. Do the individual stores need a paid monthly account or just a regular account?
4. How do I get PayPal Sandbox API Credentials?
Sorry that I am so PayPal illiterate.