The model of your gun is nicknamed "the sidekick". It was produced between the years 1956-1985. It's mainly used for hunting small game. It came in 3 different barrel lengths.
2.5" barrel- $71.00
4" barrel- $86.00
6" barrel- $106.00
50-110 or so
$25-$175, depending on model and condition.
25-150 USD or so
That is the serial number- not a model number. Try again.
No way to tell.
Blue Book of Gun Values
10-130 usd
Have you tried a web search? Local Library? Do a web search on Harrington and Richardson Books and you will find some sources.
Harrington & Richardson did not make a Model 1900. Hopkins and Allen did.
20-140 usd
More information needed to determine model of firearm.
"BB" prefix indicates 1985