The Marksman Repeater doesn't use a C02 Cartridge it a spring operated pistol
They sell C02 Cartridges for any pistol but I don't believe they sell the Umarex brand. However all c02 cartridges are universal and interchangeable
I also have an 8G BB gun and I use the 8G N20 Seltzer cartridges in it and have had no problem. I also use "Crosman Pellgun oil" Or "RWS oil." I put a drop on the tip of the cartridge before I insert it into the pistol. This keep the pistol lubricated internally when the tip gets punctured. C02 cartridges have oil in them N20 cartridges do not.
Use C02 to propell the pellet
C02 12 oz cartridges of any brand will work with your 160. Basically they are all the same. You can find them at most all sporting goods stores or Walmart or any paintball store.
You can buy ink cartridges from Office Max. If you have a cartridge that is out of ink, you could pay $10 to refill your old ink cartridge. If you want to buy a new one, they have a wide selection of cartridges.
Staples.com has a wide variety of ink cartridges, and will often give you money back for old cartridges. Staples should have compatible cartridges for you.
If you are asking about the small 12 gram C02 cartridges, then,"No" they are not reusable. However, larger tanks (like 20 oz) with pin valves on the top are refillable.
Where is local? Walmart sells CO2 cartridges
Only some need c02 cartridges in them, but most don't need air, no.
You can purchase pro jet cartridges at your local retail store or at any store that lets you recycle old use cartridges for new ones half off since its green to go.
Buying refill kits for ink cartridges is much more economical than purchasing brand new cartridges. It is even possible to send your old cartridges out and have them refilled and sent back.