Impossible to answer without knowing what your intended use is. Both are useful in a variety of situations.
100-500 or so
Go to Wikipedia.com and look up the cartridges. They will tell you the ballistics and everything you need to know about the two cartridges. You will see the 500 Magnum is worlds away from the 44 magnum!
100-500 or so
There are many handgun rounds that exceed the 44 mag. 454, 460, 500 to name a few.
It says, the 44 auto-mag. As you see it fits, it's just a semi-auto 44 magnum. Look it up.
100-500 usd or so
100-500 USD
500-1000
100-500
200-500 USD depending on condition.
100-500 USD
100-500 or so