It's not that hard to make your own. Especially if you make it a community effort where someone who has the time and inclination can get ingredients from everybody else, make and jar the ketchup, keeping a cut for themselves.
Failing that, though, there's plenty of ketchup recipes out there you can follow slavishly at first, then, as you get more comfortable with making it, experimenting with your own preferences. Start off with small batches until you get a feel for making it right, then start making huge batches and canning them for long term storage.
- Here's a simple recipe: https://www.youtube.com/watch?v=RVncvjU0KFI
- Here's a more complex one: https://www.youtube.com/watch?v=jRRp05TBBec
In either case adjust to taste with the sweetener (trying it once straight to get the baseline first). My personal recommendation for sweetener is brown sugar, but I'm weird.