Below is a simple program that represents a complex one that the user is presumed to require and thus should be willing, but not anxious to pay a monthly fee.
OPEN "TheData.dat" FOR INPUT AS #1
INPUT #1, n#
PRINT "Last data was"; n#
INPUT "How much do you want to add"; a%
n# = n# + a%
OPEN "TheData.dat" FOR OUTPUT AS #1
WRITE #1, n#
(Of course you have to take care of the initial case which creates TheData.dat)
Now modify that program so that it only works if the user inputs a password each month. Each month the program will print out a code word to be sent, along with a paypal payment of $10,000 to the author. The author will get the cash and, using the code word, prepare a password that will enable the program to work another month.
Assume the user cannot disassemble the code or modify it. Make a system which the user cannot trick by changing the date/time, erasing recent files, editing the Registry, etc. A really secure system.
You obviously need two programs, the one above (modified) and the author's program which will generate the password, given $10,000.
I believe it can be done and will do it myself if nobody else can.