No, unless it's a mint/awesome kegerator that's a poor deal.
Depending on the size of the co2 tanks, they run $40-$70 new. Two cornies will be $50. A double chrome tower is probably about $100. A used fridge can be $50 or so if you look on Craigslist.
If you really want the small kegerator with a tower, already converted, it might be an "ok" deal to avoid all of the work yourself. But you'd still want to change the beer line out and put new line on, and it's a PITA on a tower sometimes.