If you are bootstrapped and need low cost recurring payments capabilities here are a few fully outsourced and PCI compliant services you could consider:

PayPal Website Payments Standard: 2.9% + $0.30/trans https://merchant.paypal.com/cgi-bin/marketingweb?cmd=_render...

Google Subscription Payments (experimental): 2.9% + $0.30/trans http://code.google.com/apis/checkout/developer/Google_Checko...

Aria SubscriptionPlus (via PayPal partnership): Free trial, then $40/mo https://merchant.paypal.com/cgi-bin/marketingweb?cmd=_render...