Dynamic information box

Hi everyone, I’ve been toying with this idea for a while and was just wondering if anyone could point me in the right direction so I can get this started.

Basically, I want to make an information box that will sit within a side bar that gives some basic information (including an image and related posts) incredibly similar to the one found on the right hand side of this post – https://www.computerandvideogames.com/368538/game-prices-wii-u-models-at-pound260-pound310/

I have a feeling that I’d need to make some kind of custom field at the bottom of a post, that calls this information in from a database, but I’m not too sure.

Any ideas?