Second hand graphic card

Assuming the card has not been damaged in any way, a used card should work the same as a new card. You do have to be very careful when shopping around for second hand cards. There is a good chance that you could run into a damaged card that someone is just trying to get rid of. Older cards also won't last as long as a new one, especially if the previous owner was overclocking, or running it in a case with poor airflow. Another issue to worry about is that the thermal compound on the cards breaks down over time, leading to overheating. It is possible to reapply the thermal compound when needed, though it is an extra hassle, depending on how old the card is, you may have to do this soon after getting it, rather than several years after purchase in the case of new cards.

I personally would just save up more to get a new card. Used cards are usually not under warranty for any owner after the first one, and there is always the risk of getting a damaged card. I would only get used if I really needed to upgrade some ancient system that can only use cards that you simply can't get new anymore.