Mine were given to me by someone who didn't wanna take them to the scrapyard since the beer store he bought the halfs at shut down and he had them in his garage empty. I just paid him the deposit fee of $30 a piece which wasn't bad. After everything was said and done I still paid less for these two then I did for one decent 15 gal kettle.
Try that for the conversion though. Honestly its VERY simple with a step bit, I have barely any DYI experience and it was easy.
Also check out some of the vendor lists on here for the hardware u will need, dip tubes, false bottoms, sight glasses, thermometers, etc. I get most of my stuff at www.brewhardware.com since a lot of the guys here recommend it and one of the guys here runs it. His stuff is top notch but there are others here that make great hardware as well.