If you need more requests than you have on your hosted Post Affiliate Pro/Network account, you have to upgrade your plan.
For example if you have Basic license of Post Affiliate Pro (500,000 tracking requests per month) and you want more, you have to upgrade to Professional (1,000,000 tracking requests per month).
What if I have the biggest version of Post Affiliate Pro/Network ?
If you already have Post Affiliate Pro Ultimate or Post Affiliate Network Enterprise, then you can purchase additional tracking requests
Price for additional 10.000.000 requests on Post Affiliate Pro Ultimate is $100.
Price for additional 10.000.000 requests on Post Affiliate Network Enterprise is $140.
NOTE: 10.000.000 tracking requests is the minimum that can be purchased in addition.