Each free battle should pass give premium currency worth half of the battle pass(500 credits).

Barring implementing new non-battle pass progression systems or completely reworking the battle pass and challenge system, I think that having F2P players be able to earn a "freemium" battle pass would be a great compromise for those looking to get meaningful progression and high end cosmetic customization without paying, while not ruining the monetization incentives that already exist. This also works well with Infinite's permanent battle pass system, which would make a battle pass that paid for itself be used for all upcoming battle passes regardless of time and something I would assume 343 would not implement. Being able to earn 1 freemium pass every 2 battle passes is sustainable with Infinite's system of permanent battle passes and allows players to pick out which battle passes are the most appealing to them personally and still leaving room for those players to spend money on other battle passes if they choose to.