The Harrington & Richardson Mdl 150 is worth about $125-200, depending on condition.
Need more information. I Cannot find a reference to an H&R Model 25 bolt action rifle
Need more information - I am not familiar, nor can I find a listing for a Model 25 bolt action rifle made by H&R. Check barrel/receiver for correct model number.
20-500 USD or so depending on specifics
The Marlin model 81 is a bolt-action rifle.
It depends on the particular model of the rifle, not the caliber it is in. What model and make is it?
Have you tried a web search? Local Library? Do a web search on Harrington and Richardson Books and you will find some sources.
100-300 USD
$200
50-100 or so
$100
Yes