How to buy WoW game time without subscription?

I'm curious to know, what are the steps one can follow to purchase World of Warcraft game time without having an active subscription? Is it possible to directly buy game time credits or tokens through the game's official store, or are there alternative methods that players often use? Additionally, are there any potential risks or limitations to be aware of when opting for this approach? I'm looking for a comprehensive explanation that would help me make an informed decision.