You MIGHT need a ball lock tap set. These are around $15.
I just finished doing a LOT of research on kegerators. I came to the conclusion that if I was not willing to either convert a freezer, or spend over $700, I would be throwing my money away on frustration. I chose to spend more money because of how I want it to look in my basement.
I did have an opportunity to physically see a $500 kegerator at Mennards, and I can honestly say, if I actually spent that kind of money, and that is what showed up, I would be really upset. You may want to take a trip to Home Depot and see if they have one on display.