I'd like to get an external monitor, keyboard, etc. for my son so he actually sits at a desk from time to time . . . but have no idea what to look for. I can get a really good older Apple Cinema Display . . . but the adapters to go with it will end up costing more than the monitor! So, what the best way to go if I want something relatively inexpensive? Should I just look for a used PC monitor? If so, what adapters would I need? I've never used a laptop in "clamshell" mode before . . . so appreciate any advice you can give me!