Mushu3

Hi, I just recently found out about Affinity and have used photoshop and lightroom for years. They are not allowing us to use older versions and many are switching. Is the price for the software a 1 time fee with free upgrades for future releases? If I purchase through the app store, can I download on both my iPad pro and macbook or only one for that particular purchase? Is there any way I can try the software out somewhere before purchase? Thanks in advance for all your time and help.