Best place to buy cels?

Hi,
I also believe that some cels were won years before. I myself don't update that regularly and often times people ask me where I got certain cels.
That being said you can check also anime-beta. lots of times people post things there, also the Rubberslug shop, I often get surprised by some of the cels I find.
Also you have to consider that some people might have strong connections with Japan and their market. Frequent trips or very good friends would do it.
I guess the best that one could do is really keep checking the market regularly.

Very true. I'm also a part of the guilty party, mainly due to my hectic schedule. I guess that's why you would see most of my updates towards year's end. I try to throw in a summer update from time to time; but, it's easier for me to scan, file, & sit on it.

Visiting anime conventions may help in your search for cels. Is Animanga still around?