I agree with what was said in the above posts: I 
frame all my cels (although sometimes they do lie 
around for months before I get around to it,) and 
try not to buy anything that is clearly 
overpriced/not re-sellable.

I don't actually consider myself a cel collector, 
I buy them as art to decorate my house, and have 
a relatively short list or characters/scenes I 
want.  It's probably unlikely that I'll actually 
stop buying cels once I have everything on my 
list, but hey, everything's possible. :)

Another thing that helps me with budgeting for 
cels is being extremely picky.  I only buy cels 
that look "perfect" to me and that I think would 
look great in a frame on my wall.  Because of 
that, cels I want do not pop up very often, so 
I've averaged one cel every month or two since I 
got into this, ranging in price from very cheap 
to quite expensive.  I also tend to keep money in 
my PayPal account just for cel purchases, so that 
by the time a cel I want appears, I already have 
the money put aside and don't need to re-budget 
my income.

And a final thing: if a cel goes unframed too 
long, I decide that I don't really love it after 
all, and get ready to sell it.

Reene