Here are some Groovix printer recommendations as of 2016-09-01. Printer and toner prices can fluctuate a lot so you should definitely double check these figures before purchasing.
In general you only want to consider printers that support postscript and PCL and have at least 128MB of ram, ideally 1GB plus for larger installations.
The monochrome HP M402 , monochrome HP M604, and color HP M553 series printers appear to be some of the most economical printers available.
example comparison for monochrome printing:
printer: upfront cost plus toner to get to ~ 10000 pages, replacement toner cost
M402n: $200 + $175 toner = $375 , $175 for 9000 pages = 1.94 cents per page
M604n: $500 , 1.6 cents per page, $175 for 10,500 pages = 1.66 cents per page
M553n: $479 + 1/3 of a $175 toner = $537, $175 for 12,000 pages = 1.45 cents per page black
The HP M402 with a 1500 page toner plus a full 9000 page toner costs about $125 less than an HP M604 with 10,500 page toner. If a location had low print volume and the 128MB memory of the M402 wasn't an issue due to people printing lots of high resolution graphics, and upfront cost was a major factor, the M402 might make sense. But the M604 is probably going to last longer. If you will print over 50,000 pages in the lifetime of the printer the cost per page for replacement toner makes the M604 a better choice.
However, the color HP 553 series appears to compare very favorably to those two, both in per page replacement toner and up front cost ( including m402 toner to get up to the same pages that are included with the others ) . I suspect all the extra moving parts of a color machine make it less durable, but if you're only going to have one printer at a branch it would seem the 553dn is hard to beat. Compared to other color laser printers the HP 553 series is clearly the most economical unless you have extraordinarily high or low color printing volumes. If you have enough volume to justify a second printer an M604 would probably make more sense than an M402.