I know when I'm manic it doesn't look like I spend a lot but I do. I budget in an extra 200 a month for mania, which is why it doesn't hit me as hard I guess... I usually assume "manic spending" when it's on stuff like art supplies, or copious amounts of tea, or jewelry, or clothes (especially leather or lingerie... I love leather but it's so out of my price range), or sex toys. Things that arn't quite necessary, or things that I can't possibly use all of what I bought in a short period of time (like buying 3 pairs of heels... I'm just not going to wear them all any time soon!). Oh! And large numbers of books, or fabric (though that counts as art supplies) or randome religiouse things from different faiths... I'm kinda obsessed with religion.

I look for quantity in my spending, and times when "I just couldn't say no!"

That's my own personal experience with it.