I see the cheapest Lexmark is the
LEXMARK X2670 - PRINT-SCAN-COPY R620
FYI the most economical printers are these
LEXMARK PRO805 PRESTIGE PRINT-SCAN-COPY-FAX R2415.66
(It can take the Lexmark #105XL - 14N0822 black ink , high-yield cartridge that cost a mere R60)
LEXMARK PRO905 PLATINUM PRINT-SCAN-COPY-FAX R2834
(It can take the Lexmark #105XL - 14N0822 black ink , high-yield cartridge that cost a mere R60)
HP CM750A OFFICEJET PRO 8600 PLUS ( N911G ) E-ALL-IN-ONE - PRINT-SCAN-COPY-FAX-WEB R3020
Can take a very high yield cartridge that cost R200 or so.
A nice Epson has launced also for about R2668.1 Epson-WorkForce-Pro-WP-4535-DW
This one can take XXL cartridges that can print 3400 pages.
http://www.epson.co.uk/Store/Printers-and-All-in-Ones/Epson-WorkForce-Pro-WP-4535-DWF
Compare that with the cheaper printers which cartridges cost about the same but only have a yield of 500 pages or so.
These inkprinters are more economical then most laser printers
When you set above printers on Black and white mode (draft) you print a hell of a lot of documents.