Thanks everybody, I actually took my legged beer to a family reunion and while people did enjoy the beer the flavor was noticeable to my dad especially in the head. I think I am going to just have to pony up for a real co2 system. These were cross 12g cartridges btw. I can't remember if the ones from my not so LHBS had that flavor.
As long as they're not cheaping out & selling the correct cartridges designed for homebrew (the brand name escapes me at the moment, as does the place I stored my pocket charger) you shouldn't have that issue. For the 'real' CO2 system I would recommend swinging by your local welding supply shop & asking if they have any used 5# tanks for sale. Frequently they will.
I bit the bullet & bought a new one for a pretty penny. While most welding shops policy is to take your tank & give you a different one that's already filled in the back, I specifically requested they fill my tank & return it to me. I even went on the day they were scheduled to fill them. Somehow they 'lost' mine & I was given the 'best one they had in the back'. I've seen airplane wrecks with better looking metal. I sure hope the dickhead employee who stole it is enjoying all that extra money I put into it. I would never risk buying a brand new one again.
I wouldn't cheap out on the regulator though. I know Niko used to have brand new ones available, but I didn't notice if they were still posted on the NikoBrew.com website. Plenty of the other sponsors carry brand new ones. I would only suggest not buying from KegWorks. I returned the one I got from them a few years back - real cheap crap. The little extra for a 'gauge cage' is a really good idea as well.