So about APEX.
APEX is currently about 35 gold and will probably only increase in value. It is the equivalent of 1250 credits, you need 2 APEX for one month of patron so around 70-85 gold a month.
The thing is, it is significantly easier to make money once you are already a patron with farmland. I am making about 15 gold a harvest and I can harvest every 2 hours, granted the market is young and there is a high demand for cotton. I am not really sure of other ways to make money but this is what I've been doing. Maybe leveling a profession could work for you too.
So it is definitely possible to buy your months with in game gold, however you may have a tough time getting that first month. And you are going to need to out produce the 80ish gold a month in order to still make a profit from all the work you are doing.
Idk, I'll definitely do it but I'm broke and good at making gold.