Tail?

[Tyla]

You could try creating your own means of doing it; airbrushes, templates etc. My friend managed to do it. :p

[Xywolf]

you could always try a fancy dress shop if you wanted i guess.
but theirs alot of people in the fandom who you can commission to make one for you. me for example ;'D

check FA?

[FoXTAlL]

Mine is also real. I got it from a fellow who said that he got it from a coat factory that was throwing it in the trash. I'm against killing animals for stupid reasons. but I figured better with me than a land-fill. (I believed the guy because he looked like sort of a tree-hugger.

[Birlioz]

I haven't seen any nice tails in any shop whatsoever. You can usually find tails in the pet supplies section, but they're attached to toys and stuff. Not hard to remove, but not high quality in the least. Hot Topic also sells them, but I think they're nasty.

I would definitely recommend finding someone to commission, or making one yourself. I know these have already been said, but I guess I'm here to back it up

[Takarah Luna]

Uh... I've looked on EBay... But I don't  really know how to define a "good" tail... But I've  found several...