I thought I posted this question before, but I guess it didn't go through. How can I handle when clients want Multi. events some you pay for and some you don't. I can't figure out how to add the buy now option only on the events that they have to buy for and not have it show on events that are free.

I don't want people getting confused thinking because they see the buy now option that the free event is a paid event.

The payment system is enable/disabled at the component level.
ABPro has no ability to turn on/off the payments based on resource.

If the total due = $0, ABPro will not send the user to PayPal, it will just add the booking.

About all I can suggest is rather the the default PayPal 'buy now' button, you use a non-image button with generic text like 'Book Now'. If there is an amount due the customer will get sent to PayPal otherwise not.
If you clear out the 'PayPal button image URL' box (ABPro|Payment Processors|PayPal) then ABPro will put up a simple button.