some days ago i played campaign and i was earning only 6 credits per spree and nothing for the kills, i thought maybe that day the was some problem so i tried it even today but without sucess i am earning credits only for sprees and only 6. can someone help me!
The only explination I have for you is that at some point in your commedation progress, you stop making a lot of credits in campaign.
> some days ago i played campaign and i was earning only 6 credits per spree and nothing for the kills, i thought maybe that day the was some problem so i tried it even today but without sucess i am earning credits only for sprees and only 6. can someone help me!
you do not get many credits in campaign. most of the time you get less than 1,000 cr no matter what difficulty
You stop getting credits for individual commendations once they reach silver in campaign.
the fact is if I finish a campaign mission i get around 100 credits and i don’t have Gold membership so there is no way to get credits… so i must buy a gold membership to gain credits? because from capitain i got to major only with campaign and now it is not giving me more credits so i can’t grow anymore. 
anyway thanks for the replies! hoping to get a better explaination…
if no gold then you can still get 200k everyday.
https://forums.halo.xbox.com/yaf_postst101997_What-s-the-fastest-way-to-earn-credits.aspx
Commendations stop paying out cR after they have been advanced to thier silver state, and will only pay out cR at milestones except when they are maxed out.
If you want to earn cR using campaign, use the custom challenges.