It really comes down to decide between buying a relatively cheap 500-800 all in one for home office use, the dowside of which is paying around 100 for toner cartridge that will net 2500 pages tops,
Or going for a proper office machine that will cost you between 1500-2000 depending on options but uses cartridges that cost around 30 quid and print 15000 pages.
Refurbished machines are a prefectly fine option, but only if they come from authorized dealership. Buying them from ebay is generally a bad idea as you may end up with a machine the fixing unit of which or rollers are at the end of their service life and you will likely end up having to call dealership for service and spare parts to tune of buying a refurb machine straight from them.
Many dealerships lease machines to companies, and they often resell those very same printers later on with heavy discounts.
You may want take a peek at imageRunner series from Canon, not the cheapest, but very low running cost. They also provide drivers and tech suport even for stone age machines of theirs. Same cannot be said about Samsung, HP or Epson.