The answer depends on where you live, how old you are, exactly what you are selling, how old the buyer is and whether or not any federal or state laws come into the deal.
How much can you sell a car for? Depends on the car. Your answer depends on the pistol. There are inexpensive 22 caliber "pocket" pistols that sell for about $50-75, and VERY pricey .22 caliber Olympic competition pistols that are $1000- and up.
You cannot purchase a pistol grip for Hatsan/Escort shotguns. It is illegal to sell/buy pistol grips for any shotgun mfg. outside of the United States.
50-200
They sell in the range of $40 to $90 dollars
How much is a car? Depends on the car, and on the pistol. A Jennings J-22 might sell for $75. A Ruger Mark II heavy barreled target pistol- $375. An Olympic grade Hammerli- $1,075.
No
put an ad in: gunboards.com buy/sell board
Are you looking to buy, sell or trade?
A Jennings model 59 9 mm is a type of pistol. Many people try to sell this pistol for anywhere between seventy dollars and over two hundred dollars, the value is determined up the use and care of the pistol.
They sell C02 Cartridges for any pistol but I don't believe they sell the Umarex brand. However all c02 cartridges are universal and interchangeable
Auction
An internet search engine, with the make and model of your pistol will bring up a whole slew of folks, eager to sell you gun leather.