John Kort said everything I would have said.
But I'll add:
If your rifle has a rimfire firing pin, you're temporarily out of luck. No one has offered .32 rimfire ammo for some time. Old Western Scrounger had it about 10 years or more ago. Navy Arms offered it about 20 years ago. Both offered .32 rimfire ammo made in Brazil. Apparently, the munitions plant in Brazil is no longer making it, or exporting it, because I've searched for a modern source and still can't find it.
If you rifle has the rimfire firing pin, the little nub in the face of the bolt, that functioins as the firing pin, will be on the side of the circle worn on the bolt face. If your rifle has a centerfire firing pin, it will be in the center.
If your rifle has a centefire firing pin, you're in luck.
Winchester still makes .32 Short Colt ammo, which will fit in your rifle. It may not feed well from the magazine. Mine does, but I've heard that some Marlins balk at cycling .32 Short Colt ammo. You won't know until you try (at the range, with the rifle safely pointed downrange).
Figure on spending $30 to $40 for a box of 50 newly made Winchester .32 Short Colt cartridges. I lucked out a few years ago and found two boxes at $20 apiece, but that was on a discount table. Perhaps you'll be lucky too. Large sporting good stores with a large variety of ammo like Cabela's, Gander Mountain and Sportsman's Warehouse might have it.
If you don't have the centerfire firing pin, Wisner's sells them for the Marlin 92 for $22. Go to http://www.wisnersinc.com/rifles/marlin/rflever.htm
Save the empty cases. Even if you don't plan to reload now, you may later.