when buying a tree stand I recommend NEW one, for safety reason's
as all things age and get weaker and or can be damaged, pending HOW the old owner took care of it

LIKE IF say a LOC on and they dropped it a few times from say 20 ft up, you MIGHT not see the damage, but could have weakened welds??

SO< new is a better way to go

after that you want to decide on what type of stand you want?
a loc on, climber, or ladder stand
Laddderstands to me are the safest, as long as quality made that is.
they offer you the chance to get in and out quiet, can come in all different shapes and sizes, and can be enclosed and some are down right comfortable

Loc On, are to me Bare Basic in a stand, some are for sure more comfortable than others, But never really used one that is as comfortable as a ladder and or climber
but there also typically the cheapest option on a stand, UNTIL you add in the climbing sticks or steps ? then prices can climb, BUT they can be used in a lot of spots other stands cannot
a Climber is a nice option
they allow you to move at will, and can be set up pretty fast, and again some of them are super comfortable,
just remember all STANDS that use straps and likes, the straps were out and need to be replaced every so often
MOST folks like to add second straps over the OEM set up for added safety
the Bands on climbers also have shelf lives, I know my Lone Wolf climber , there only rated for I think 6 yrs and have to replace, or recommend there replaced

I suggest going to a place that carry's a bunch and look and see what you like and go from there!

LOTS of quality stands on the market now
Good luck!