Marks are automatically put in your inventory and can be spent immediately (provided you have enough for an item). You are limited to 100 marks per week for each Crucible and Vanguard. ** Any additional marks for a week over that 100 will not count and will not be transferred to you later. They vanish into the ether. The weekly reset does not affect the marks you currently have, it only allows you to start making more marks that week (up to the cap of 200 maximum per faction). Unearned marks also do not carry over. With 100 vanguard marks from last week, you can earn up to 200 this week. With 38 Crucible marks, you can earn up to 138 this week. Note that Reputation is very different from marks. There is no cap or limit on reputation gains, which is good since you need thousands. Hopefully some of this helped.