There are a few things that you need to take into consideration when looking for a mini fridge. The first and most important, is how much can it store on the inside. Most people do not realize how small a mini fridge really is until they start to store things that are not soda cans. Luckily, some of these mini refrigerators have racks that are removable, but you'll need to make sure of it.
The other thing to also remember is if you want to have a freezer or not. Some of these small refrigerators have a small compartment at the top so that you can make ice with ice trays, but they're so small that it's not possible to really store anything else there. You can read more about mini refrigerators here, but keep in mind that these things are expensive. I would suggest that you take a look at them in a store before buying them online.