Yorkie: Your right, the color on the monitor is always off but I am mostly a scrappy quilt maker so it isn't so important. I am always pleased with the color even if it isn't quite what I had invisioned. Plus paying $4 per yard rather than $12 encourages me to adjust. If you are just stash building you can do the matching once you get it in hand. I just recently placed an order at CT for an entire quilt top. Don't know whether the colors will work together, but at their sale price I thought I would try. For me, the good price makes the risk worth it. It is a question you have to ask yourself. Some of the sites have "color walls" where you can point to a particular color in a fabric you like and the program will pull up like colors in other fabrics. Really a lot of fun to play with.
Connecting Threads and Fabric.com both have free shipping for a minimum order but even if shipping is an additional cost I just divide it by the number of yards and it is still a very good deal.
Guess what I am trying to say is that I have been very pleased with my on line experiences, the service has been great and the prices have been superior. Hope this helps.