I guess it depends on how much printing you do.
My Canon inkjet (top quality photo printer) has 5 individual tanks. The main black one costs £9.69 delivered, and does 5500 pages of A4 text. Possibly a laser would be even cheaper, but I can live with being able to print 5.6 pages of text for 1p. The colour tanks are £7.89 each.
I'm with Bill - depends how much printing you do. I've got a canon A3 printer with seperate print tanks. The electronic bits built into the print heads get changed less frequently.
I use Tonik.co.uk for ink tanks & print heads and generally use their own brand ink tanks as I don't do much high grade printing. Their service is good and they have replaced any faulty items without question.