lager fridge temp regulator

i looked at the first few pages of the DIY forum for any information on parts to convert my mini fridge into a lager fermenter. i've seen equipment before that allows you to control the temperature of a fridge. i was wondering if there was an economical gadget that would work for a mini-fridge (large enough to fit a 5 gallon plastic bucket). if any of you have links to the info as well, please post that. thanks in advance!

I have a mini fridge that I am in process of converting to a lagering fridge. I have a Johnson regulator that I am putting in and there are regulators from Ranco, the cost will be between 30-70 for these. BUT Check out your mini-fridge to see if your 5gal fermentor will fit. For mine, which is a vary common design for a mini fridge, the compressor is in the back bottom so the depth at the maximum hight is only about 8-10 in. This is not large enough for a bucket but will work for a cornilious keg if you remove the door shelfing form the mini fridge.