What is the best heavy duty concealer that won't cost a fortune?

I am in desperate need of a heavy duty concealer for dry, dark circles of the more purple kind. I've tried 3 concealers so far (Physican's Formula Concealer Duo Light/Yellow, Revlon Age Defying Moisturizing concealer and Maybelline New York cover stick) They were all either not giving enough coverage or they caked very badly and sank into my fine lines, making me look even more tired.