Don’t worry, 90% of our users won’t have to pay anything at all! Just ignore that like 50% are people who downloaded Unity to mess around for a bit and never made anything other than a “hello world” or similar.
If you’re enjoying it, I would recommend checking out the rest of the series too. They all emulate well enough, except the PS2 games but they have PSP ports that emulate almost perfectly. The PS3 games might still be purchasable.