You should be able to get the first four used for about $200-$300. Dunno about the Kral, still too new. You could do a review and test them all with the same pellet. Then test them individually for the pellet that shoots best in each gun. You may very well find that one is considerably more accurate than the rest without being a bear to shoot and cock. Then again you will likely spend more time hunting for accuracy from these guns than actual hunting, or plinking, or target shooting.
Of course you could just pony up the $200-$300 for a nice R9 or HW30 and never look back.
Up to you.
I would pick the second option.
Just sayin.