Runway sells a suite rather than a single generator: text to video sits alongside inpainting, motion controls and a timeline editor. That breadth is also why the credit maths matters more here than on a simpler tool: one grant has to cover several different kinds of work.
What the free plan actually buys you
The free plan grants 125 credits once, not 125 credits a month. That is the single most important line on the pricing page and the easiest to misread. Synthesia, Pika, Descript and HeyGen all refill monthly; this one does not. Once those credits are spent, the account keeps working but cannot generate.
The entry price is the struck-through one, not the one in the title
This profile carried no entry price for a while, because the Standard card prints two monthly figures side by side and an earlier reading could not tell which applied month to month. The card answers it now: $15 is shown struck through beside $12, under the line billed annually, save $36 per year. Three dollars a month across twelve months is thirty six, so the two figures and the saving agree with each other.
The number at the top of this profile is $15, and that is deliberately not the number Runway leads with. Its own pricing page is titled from $12 a month, which is the rate for committing to a year. If you want to be able to stop after a month, $15 is what you pay.