I have done all the hard work for you and narrowed down a few of my favorites as far as places to go for your new digital art! There are literally thousands of options for you but here are a few of the places my clients have tried and liked. Obviously I cannot guarantee your satisfaction from these companies but people have had nice items made from these vendors.
This framing option is a company I am amazed by. They are more traditional but have lots of options. They have so much to offer here and I think they are pretty great quality. They are able to purchase in such huge quantities that they are very reasonable for clients.
This one is called pictureframes.com
Artifact uprising...I love simplicity!
Modern and clean. I love the simplicity of this company
This is the baby sister consumer version of my flagship company. They do fine work and I think they print closely to what my professional lab does. This is their consumer printer line. They will take care of several types of print options and I believe you will be able to create cards, books, canvas and some specialty prints as well as a few print and frame options here. Maybe a one stop shop. You will have to load all of your images to their website though. A little clunky but worth the effort. These prints will come closest to resembling the professional print.
It's called MPIX.com
Now for a special card printing company. Of course there are many but I tend to prefer two different ones...They are less "cheesy" and have nice quality designs.
There's your list of special places I like to recommend. While Walmart is an option it is not my choice. I also do not recommend Shutterfly for wall prints although their cards are getting better (They do leave a huge advertisement on them so be aware of that). I'm not sure what they do to the images but I believe they run through an automatic filter that changes all of my hard work of editing properly for print. I always recommend printing the wall items through me if possible. There is an art to printing large.
Enjoy your new art! And PLEASE tell me if you have problems or questions.