Yeah a bit... they can be had for less on amazon.. but still going to run you around $40 per. On looking again at them, they're only 12" deep. That may not be enough depending on what you plan on installing.
The ones that were given to me actually are expandable depth as well.. not sure where they came from, but I like them.
Sometimes there are places that liquidate old telco equipment, computer & office equipment. Depending where you are, there may be something like that around you. Stuff like that can be pretty cheap if you can find it.