A classic computer: the DEC PDP-8/S
Total cost was approximately $17,000 in 1960's dollars, enough money to buy more than a half dozen automobiles. In addition to programming it, we conducted experiments on its 2nd generation discrete transistor circuitry, and learned the fine points of computer science quite well. We also used the School District of Philadelphia's Hewlett-Packard HP-2000/C cluster via timesharing on our other ASR-33 teletype.
To see detailed historical information and many pictures of PDP-8/S internals, click here. To see a front panel closeup of a similar PDP-8 computer from a virtual computer museum, click here. Yes, I know what all those lights, labels and switches mean. Today's computers lack the direct feedback on internal operations that classic machines gave users. This is unfortunate; the computer has become a magical "black box" to many. This is one reason why many are now in awe of or controlled by computers instead of in control of computers.
Here's a modern picture of a restored machine merrily flashing away (courtesy "PDP World" by email@example.com, http://www.pdp8.com/):
Here's a picture of a PDP-8/S, in desktop cabinet, from a 1967 DEC book on logic modules: