Also unclear on the question. For example, I pay for an annual Ultimate Subscription which gives me $270 worth of tokens. I use way more than that, but simply resubscribe multiple times a year. For example if I pay $270 for the annual sub on Jan 1st and on April 1st I've exhausted my limit, I simply resubsribe and pay another $270 for another $270 in credits.
Per @BLACK 's comment, I could see the request for ala'cart premium tokens if someone didn't have or necessarily need an Ultimate Sub, but wanted temporary access to the full RA for a project or whatever, but I don't know that that's what the OP's (@bitjammer) post was inquiring about.