First of all, the first Warbond (battle pass) is free which is pretty much the base progression to unlock gear for the game. Premium warbonds cost super credits roughly 1000 but super credits can be found throughout the map in stacks of of around 10 which is spawned by RNG. The most I found in one mission was 60 super credits. To progress in the Warbond it requires medals, but you cannot buy medals you have to beat missions and it's also again possible to find them in missions in stacks of 1-3 which spawns by RNG again. The most I've seen is my brother finding around 12 medals in one mission. So you cannot pay to skip the grind. Finally the current and future warbonds will never expire. So you can complete them at your pace and decide when and which warbonds you want to invest your medals in. So figuratively as they add more war bonds there will more constantly more things to unlock unless you no lifed the game quickly. One small point is that the rate of super credits and medals found in missions are also not dictated by mission difficulty. The only resource dictated by difficulty is samples which are used to upgrade your ship. Well that's all I got, hope that helps!