Couple of options:
How to pay could be squeezed into 44
Add to title: "How do I buy a paid account for a community"
Add as 2nd paragraph: To purchase a Paid Account for a community, go to http://www.livejournal.com/pay/, select "Gift for existing user" as the item you are purchasing, and type in the community username as the recipient. Add this to your order, select your payment method, and click the button to check out.
We could then squeeze the benefits part into another FAQ (which one?) Here is a sample of the community benefits part from awhile back that got forgotten.
We could combine these topics for a new FAQ titled, "How do I buy a paid account for a community? What are the benefits to a paid community?"