It really depends on your intended use of the weapon. There are products on the market that will run you around $1,000.00 - $1,500.00 for an upper receiver that pins directly to your AR15 lower. There are products on the market that will cost you in excess of five figures that are complete firearms.
"Good rifles" exist only in the eye of the beholder. If you are serious about purchasing a .50 caliber weapon, check out the FCSA.org website. For the price of membership, you will gain access to more industry knowledge and real shooters' perspectives that would be a bargain at ten times the price. In fact, most all the current manufacturers offer discounts on their products to FCSA members, so you wind up saving some money in the long run.
Remeber, once you purchase the weapon, you are only half way there. Your optics have to be considered. The recoil of the .50 BMG is enough that you will want to have a scope that is up to the task. Not to mention that the round is meant for extreme distance shooting. If you are considering a 50 Beowulf, then you would probably want something that had a more "tactical" feel and appearance.
At the very least, check out the ar15.com website forums. There is a section there dedicated to the .50 caliber community and if you are willing to sort the wheat from the chaff, you can gain some important knowledge as well.
Good rifle, good caliber for most uses. Did you have a specific question?
Like anything else it depends on the brand, the model and the condition of the rifle. Is it still working. Is it in Poor, Fair, Good, Very good or Excellent condition
You will need the services of a good gunsmith.
It's a good caliber, yes.
Yes- a very good deer rifle.
cheap plinking rifle and low cost ammo. good for adults and youths
Have it examined by a good gunsmith. This rifle use a .22 caliber bullet, long rifle.
Depends on a lot of things. What caliber is it? Mine in 30-06 is a $1000. rifle.
Shotgun with buckshot, 30 caliber rifle, etc.
In good condition $150
The value of the Stevens .25 caliber lever action rifle varies quite a bit with its condition. This gun sells for about 300 dollars in good to excellent condition.
The 950 JDJ is not intended as an ultra-long range cartridge. There is no sniper rifle in that caliber.