paypal API subscription question

You can download API here
https://www.x.com/developers/paypal/documentation-tools/paypal-sdk-index
and some example
http://phpfour.com/blog/2009/02/php-payment-gateway-library-for-paypal-authorizenet-and-2checkout/

ok...thank you....appreciate it...
but I'm asking if the recurring subscriptions can be told how much to charge per month vice a single amount at the beginning of the contract....

No, recurring payment / subscription cannot have different values for different period

As sivagnanam_c mentioned, recurring payments / subscription profiles cannot have variable amounts.  

However, you could utilize the Preapproval API in combination with Pay to build your own subscription model that does allow for variable amounts.  

Another option would be utilize Authorizations and Reference Transactions.  With this method you could simply authorize $1.00 on the person's PayPal account or credit card, then immediately void that authorization.  You could then use that transaction ID you got back from the authorization within DoReferenceTransaction to charge any amount necessary at any time in the future.

In any case, PayPal would store the billing information for you so that you don't have to.

ok...this is awesome...
do you know of any references that has examples to these options?

Thanks so much.

Thank you so much...
Appreciate the time....
Is there a method to ask further questions?

Yes, you can ask questions on here, of course, or you can contact me directly.  I offer 30 min of free training on my library if you'd like to get comfortable with it.  We can do a screen share and I can show you how it all works.