Society 6 is an online marketplace for artists to sell their work. When you buy something from an artist, it's produced by Society 6 and shipped to you on the artist's behalf. You can buy everything from high quality framed prints to iPhone 4/4s covers to laptop skins and t-shirts. A simple search for a term like "vintage typewriter" pulls up plenty of high quality and artistic options, which you can easily turn into stationary or a canvas print. Art.com is exactly as it sounds: a great place to find art. The site features a diverse range of vintage art, including these stunning old covers of Popular Science Magazine and drawings of the original printing press.
It's been said before and it will be said again: Etsy has everything, including plenty of artistic takes on vintage pieces, which can be easily integrated into any office design. Stores like mymimi are particularly fun to shop, because they combine the practicality of items like a pillow and combine it with a bit of whimsy. Their cassette tape and tube TV pillows are charming AND useful.
Always keep your eye out for hidden gems in specialty online stores. For example, photography site PhotoJoJo's store is full of interesting pieces that will delight photographers and pique the interest of house guests. Their Vintage Camera Mobile can work as a statement piece in an office or a cute alternative to a baby's mobile. Products featured above (clockwise from top left): Joystick #04 by Kris Efe, Typewriter stationary by MakerMaker, Printing Press print by Applegarth and Cowper and Black Cassette Mini Pillow by mymimi. (Images: Kris Efe and MakerMaker on Society 6, mymimi, and Applegarth and Cowper via Art.com, Popular Science Magazine and Photojojo)