Lots of people are using small fridges or wine coolers for such efforts. One thing to keep in mind is that these have much smaller volumes than full size fridges, and often have cooling elements directly exposed within the chamber itself (esp. for small dorm fridges, and maybe less so with wine coolers). These two elements combine to make temperature and humidity regulation more difficult especially if you are trying to do it all by hand. But if you get things set up with a microcontroller, it is eminently doable, and you can end up with great results. Depending on your level of tinkering skill (or your level of frugality!!!), you can do it really cheaply given that you already have the wine cooler.
In my case, I have a dorm-size fridge, and using an Arduino microcontroller with a temperature/humidity sensor, a mini ultrasonic humidier, and 4 channel relay module, I have set up a solution that works well to control the setup.
Basically, I have the microcontroller check the temp and humidity every minute. If the temp get to 14°C or higher, I turn the fridge relay on, and keep checking the temp every minute. When it cools down to 10°C, I shut off the fridge via the relay. So the temp varies up and down between this 10°-14°C range, and averages about 12°C overall. Similarly, with the humidity, it is being checked every minute, too, and if it drops below 72%, I use another relay to turn on the ultrasonic humidifier for a few seconds. I keep turning it on every minute thereafter until the humidity gets back to a comfortable level.
You can get most of the parts for what I am talking about very cheaply (
