What to buy with 100 coupons

Apologies that its an old question but for me i really have no idea what to get.

I already own the M4custom,AK camo,Ak gold,Deagle gold,Aug camo,Deagle camo.

I am not really into sniping anymore I find it too boring to just camp and wait and cannot master this quick scope business .So AWM camo is probably not worth it for me.

I Also never play ghost mode or knife only matches as I am terrible at both.Which rules out the axe.

So it kind of only leaves the AK knife,M4 gold or the M4 crystal(i already own the M4cc).

Any ideas what to purchase or should i just wait(as i can't open any more crates)?
Any advice would be appreciated.