The trial version is the same as the Registered version. The only limitation is the trial version will stop working after 30 days (well, maybe 31). If during the trial period you decide the program is worth the cost and you buy a license, I will send you a small text file to save in the same folder where you installed the program. When you restart the program you will not have a trial version anymore and you will have a license to legally continue using the program as long as you like.
You can't reinstall the program to get more time, Or reset the date on your computer to get more time. If you decide to buy a license you will receive a text file to remove the trial limitation and continue using the program as before - even if you let the trial expire before buying a license. The 30 days is from the day you install the program - so please don't install it until you know you will have time to evaluate the program.
No. Church Secretary for Windows is not designed to run on operating systems other than Microsoft Windows. I have developed a similar program that is browser* based and runs on just about any computer or phone that has a browser. That program can be hosted for your church by me, but I have not yet rolled that program out for the public at large. It would be a continuing cost unless you bought a license and set up your own web hosting and paid them for the monthly or yearly costs. You would have to pay your hosting company year after year, though. Something to think about. Church Secretary for Windows 2021 is a one time purchase. * The screen shot page shows images of both the Windows desktop based version as well as a few screen shots from the Church Secretary for the Web - not publicly available, but you can ask me about it.
No. Technical support is free to licensed users, but limited to email. So there are no support costs. The license is "perpetual", not a subscription. Once you buy a license for your church you can install it on as many computers as you like for no additional cost. Compare this to some (very nice) browser based programs. If their software in the cloud is $50 a month then you will likely be paying $600 a year - every year. It might be worth it, but for a small church it might be overkill. To each his/her own.