How long does it take to receive email receipts for App Store purchases?

I've been using iTunes for awhile but only recently got an iPhone. Whenever I've purchased music from iTunes I would usually get an email receipt same day or next day. I purchased my first iPhone app from the App Store five days ago but still have not received an email receipt (email address is correct and I checked spam folder). Is this normal? I'm kind of a stickler about keeping records for my credit card purchases and would like to have a receipt for all purchases. I read somewhere an email is sent every $20 spent or every 12 hours, whichever comes first. I've made other app purchases since then but not $20 worth. But since it's been five days since my first purchase, something has to be wrong, no? Additionally, is there a way to find and print receipts? I know you can go to 'purchase history' in iTunes and do a screen grab, but if I have to do that for each purchase here on out, that will be depressing. Also it's not much of a receipt since it doesn't show which credit card was used.

Thanks for input,

Joe