I am thinking of switching to Subscription Paypal sales, with recurring billing.
Apparently paypal sandbox doesn't play nice with the phpcoin form post page.

For now it is ok for my company, but I can forsee having to migrate to modernbill or something down the road..

The PayPal sandbox is a test environment... Unless I am confused, the sandbox is only used for testing web applications under development to ensure they work with the PayPal system before using the live paypal system and incurring charges for testing. There are also things you can do with the sandbox that you cannot easily do with paypal itself.

Now as to whether phpcoin works well with PayPal I cannot give you any advice on this as I have never used phpcoin. I do know that WHMCS is a good billing/support/management system and modernbill *used* to be pretty good if you wanted to take the time to learn it but I would say WHMCS is much better than modernbill these days.

Does it have a licensing fee? Is it a one time fee?

I have heard of it and it seems to do most of what I need.

Check it out at http://www.whmcs.com/ it's not free, but it's *well* worth what they want for it.

Check it out at http://www.whmcs.com/ it's not free, but it's *well* worth what they want for it.I second that. We use whmcs and we love it. Matt does a great job of supporting his software. We had to put in a couple of tickets to get some help on some things and he quickly helped us out. Cant see us using anything else anytime soon :)

Yes, whmcs is going for $249 one time fee. Not bad when you consider how much recurring licensing fees are.