A good printer I started with a small multifunction laser printer which I still used but have moved up to a workhorse LaserJet 5SI which I was able to get for $20. Watch for old printers from offices - universities or off lease printers. The older the printer, the bigger the toner cartridge.
Try to get a network capable laser printer for which the copies are cheap.
They will be producing invoices, lables and envelopes.