Helldivers 2

As I suspected and have now confirmed, the premium warbond is 1000 super credits to unlock. It requires no actual money. You can farm super credits in game, they are random pickups from map events, and are the only pickup not shared with squad mates. You can also pay real money for them if you want. To farm them, play single player or private on easier difficulties and you can get 1K pretty quickly as there is usually one drop per map. You can also get 1000 super credits by unlocking them in the free warbond. Each tier has 100-200 super credits that you claim with mission medals like everything else in the warbond. Note that you need to spend increasing medals per tier anyway, so you'll probably get them from at least the first 3 tiers just to get the next tier unlocked.

Paying real money only accomplishes unlocking them sooner. The community consensus on the weapons is that they all generally suck and are inferior to the standard warbond weapons, so if you were tempted to pay, use that to inform your decision. It's entirely plausible that if you wait and don't pay you'll eventually unlock them and then never use them anyway. None of the stratagems are warbond items either, and stratagem weapons are going to be your bread and butter for the most part.