What's the secret to be able to afford to not run free kits?

I want to like this game. Plenty of things I do like about it. Such as the aesthetic and the actual gunplay.

What I can't figure out is how I'm supposed to be able to afford to take a stack of green heals or 2 into a match. It seems like getting them as quest rewards is the only way, but surely you can get to a point where rearming and having supplies is not a massive drain on your stash?

My typical extract nets me about a grand of cash plus a few mods, etc. But that money barely buys a stack of heals, let alone ammunition. I know you can trade for them but that's not particularly cheap either, especially as you'll need dozens of those resources to unlock perks.

What am I missing?