try eBay that might do .
Your Marlin model 989 which was a semi auto promotional model will range in price from 75-150 dollar,depending on overall condition.
Try e-gunparts.com
Contact Marlin customer service through their website, and request an owner's manual for your rifle. They are free.
Try gun shops, gun shows, pawn shops, estate sales, garage sales, want ad, for sale ad, egunparts.
50-125 USD
On the main Marlin Firearms website, there is a section labeled "Owners Manuals", from which you can download the manuals of Marlin products in .pdf form. Assembly and disassembly instructions should be included in these manuals. See related link.
I'm not sure what they are worth now, but I bought one a few years back for around a hundred bucks..
I have used the 10-round magazine for the Marlin 795 sold by Brownells (www.brownells.com) as 550-000-337. This is a nickel plated mag. Aside from extra capacity and nickel plating it appears to be the same design as the 7-round magazine that came with the rifle (Marlin 989). Brownells also sells a 7-round blued mag as 550-707-346 that should work.
Try a thorough cleaning, change magazines, change ammunition. The marlin 989 was made in the 60's the bolt does not open when the last shot is fired
try Numrich Gun Parts Corp.If they do not have one,maybe Marlin itself may have a few still in stock.E-bay would be another good place to find a stock for your rifle.
The 99m1 was built from 1964-78. It was built to resemble the original M1 Carbine, as used in WWII. The 99M1 is the same gun as the Marlin 989 or 99C, so parts interchange with them. Answer The 989M2 is the clip-style magazine, as opposed to the tube style found on the M1 :)
He was born in 989.