You can download a demo version to decide if you like the plugin before buying. A demo version is for 30 days, after that period you have to remove the plugin or buy a product. The cost of a plugin is one time 50$ payment, we use Stripe for checkout. After paying you will be redirected to the page where you will receive a serial number which you can use to activate the plugin. You will also receive a confirmation email with the serial number. You can use the same serial number with your several devices.