I bought my wife a Xerox WorkCentre 6505. She loves it.
Looks to currently run around $550. We purchase the toner cartridges for about $18 each by not buying OEM.
We have had it for about 2 years now and it has done a great job. My wife has probably printed at least 3 cases of paper through it (somewhere around 15000 pages). The toner is inexpensive enough that I just buy 3 of each color (cyan, magenta, yellow, and black). That will set you back about $200. So for around $750, or $800 with a case of paper, your children can print all they want or need.
This is probably my fourth color laser printer and it has definitely been the best one we have had. Previously we have had Konica-Minolta, HP, and Brother. Their toner cartridges were much more expensive and it seemed like we had to get imaging units and such quite often (usually after just purchasing a new set of toner).
It also has scanning and faxing capabilities. We have never used the fax as we don't have a phone line, but you can setup the scanning to just email you the document you scan or plug in a USB drive and store it there. It has built in duplexing as well as Ethernet. Drivers are built in to windows and install was a cinch. It also worked flawlessly with Windows RT tablets we own (Surface RT Gen 1 and Nokia Lumia 2520)