Cels Forum

In addition to all the suggestions. I would suggest you not only set a limit on price but also set a limit on the anime titles. ( Well, the more anime you love, the more cels you would intend to get) 

For me, I love Jojo, YuYu, Video Girl, DNA, EVA and many other anime titles, but I would pick my favorite one and the fewest on market to collect. So that you, as a collector, would not have to say "oh man~, I love that cel, but its too expensive."

But the above is for non-commercial collector for if you like to make profit out of cel, wide variety would be nearly necessary.