.32 short used to be available from Navy Arms or try some of the local gunshows for the Navy Arms .32 short rimfire.
Is it a Model 4 or a Model 6 or a rolling block? Try posting over at http://www.remingtonsociety.com/forums/
Which version... the centerfire model or the .22 rimfire model? There is no serial number on the rimfire model 55. It was made prior to the requirement in 1968.
100-1000 USD
That's a very late Model 4, I suspect a take-down and probably a lever type? The value is GREATLY determined by condition, condition, and condition.
Which model in what condition?
Check the barrel and receiver
im almost certain its remmington Stevens Model 520
50-300 USD or so
200-275 USD
1907-1929, 100-375 USD
They are not marked, you can tell by the serial no. (well an looks ;)
Midway USA carries fiochi 9mm rimfire shotshells for the Winchester model 36 they are on the clearance page so I am not sure if they will continue to carry them.