Use a neutral colour for the cards themselves, then add colour through printing, embellishments or ribbons, or use coloured card and make a great statement. Card textures can make a big difference to the overall feel of an invitation, from rustic matte textures to contemporary pearlescent effects to vintage tapestry styles. Consider printing or foil stamping the front of the cards, or use peel_off stickers (with a steady hand!).
LOCAL PRINTING: When it comes to short run printing, the local option is my favorite option. Local print shops may not be able to match the price of many online vendors, but you get to have more of a hand in the process, and therefore a little more control over the end result. Some will even let you bring in your own paper, and most will let you use their paper cutters for free (sometimes even if you haven't printed anything through them). Unfortunately, not all local shops are created equal—some FedEx Office shops are great, others not so much. You'll need to do your due diligence to find a good match. InkerLinker is also a good place to find amazing, non_FedEx print shops near you.