First, what are you going to call this since you won't use PASS?
RDPUG = Redgate Data Platforms User Group
RASS = Redgate Association for SQL Server (I'm hoping you'll move past just SS).
RPUG = Redgate Professional User Group
RDP = Redgate Data Professionals
iRDP = International Redgate Data Professionals
Moving along, you be free for a time but things must evolve.
When you get to that point...
$10.00 annual fee from all members. Try to build that database of professionals because you can sell access to it later.
That's your MVP. Build this up anyway you can.
Attract Microsoft DB members (100,000 estimate) x 10 = $1,000,000
Attract Oracle DB members (100,000 estimate) x$10 - $1,000,000
AWS DB members (100,000 estimate) x$10 - $1,000,000
IBM DB members (100,000 estimate) x$10 - $1,000,000
HP Vertica members (100,000 estimate) x$10 -$1,000,000
Sybase/SAP members (100,000 estimate) x$10 - $1,000,000
Other data platform types.
If you get enough of these platforms, you have one for each month that you can build content around.
Each country can do a day in the month for their local users(1/2 hour sessions) with local people. The best voted presentations get to be pushed to the "RDP Summit 20xx" which get expanded to 1 hour.
The content from each of the sessions you put on youtube or host yourself and sell ad time to other industry vendors ( 5, 10, 15 seconds).
Finally, because you have dedicated Data Platform groups. The industry overall has an incentive to sponsor you because of the dedicated venues for promotion of their platform suite. This is more sustainable than what PASS had.
I need to move on to other things now...