You can buy any length sub at Phantom Overlay including lifetime & if you do not like the cheat you can make a ticket for a full refund. That's about as close to a "trial" as you're going to get from a good quality provider. I do not believe that security focused developers would sell a 24 hour key
Mobius is another example of a provider that will give an easy refund if you are unhappy. I am sure there are others too