What is the average price for a 22 cal deciblocker in US $

Pick a different manufacturer and model as half the stuff said about it was iffy at best

That will not be the hard part
unless the only weapon you have access to is an air rifle (there are no firearms of any type) read the following http://www.pyramydair.com/article/Airgun_silencers_What_s_the_big_deal_August_2006/32

Good afternoon Jay.

I found a couple .58 Cal Lyman Muzzle loaders for sale here:
Muzzleloading Rifles Modern Replica Percussion For Sale that were posted for $600. A H&A .22 rifle here
FALLING BLOCK 22 RIFLE was listing for $250 Wish I could get closer than that, but listings on H&A tend more toward shotguns and pistols, and have prices anywhere from $30 'wall guns' to $500+

Cheers
D

http://www.gundigest.com/firearmvalues

Although you didn't specify the model, it sounds like you have a Marlin model 60 of which over 11 million have been manufactured from 1960 to present. It looks like yours was made in 1975. Most of the gun auction sites are listing that model for $60-125 on average.
Marlin Model 60

http://tinyurl.com/p3qmtcl
Terry