I have used VistaPrint on many occasions over the past 5 years, when I need some sort of simple design. They are a great resource. I have also utilized them for their rubber stamps and those are great as well. I do not know how they are able to offer so many free products but I am surely glad they do.

PS Print
Another site I use when I want a small order but would like to utilize my own design and when I offer free personalized business cards to my clients with their web design is PSPrint. For $9.99 I can offer clients 100 cards I just add my promotion on the back for an additional $2 like vista print does when you get free cards from them. It has really helped get my name out there as far as my graphic design goes.