for the ink that comes with the printer, you just need to search hard:
That first laser jet has two toner sized, standard (2400) and XL (4400)
but if you look at "consumables included" in this page selling it. there is a cheeky third half standard size that the printer is included with.
*HP Laserjet Pro M476dw Colour Multi-Function Wireless Duplex Laser Printer - Ebuyer
It's a bit more difficult to make a spreadsheet for an as yet undefined amount of printing. - when I first made this sheet it was for a friend who wanted to self publish a music book, he had asked a local printing shot who were going to charge him an amount (that I can't recall) and when I first heard the total cost I said it'd be cheaper to print it yourself.
In the end he printed the book himself, (a small run of 20 books) and then managed to sell those books with enough money made on that first print run to pay for the paper, the ink, binding combs covers and pay himself at twice minimum wage for the few hours he spent binding the books...
you may find that it's useful to know what the price is per page, you might not...
as I said further up the thread for my inkjet was too expensive, in a lot of ways it wouldn't matter if inkjet was 1/10th the cost per cartridge, because MY habits of not printing very much leads to them drying up. meaning that whilst the stated capacity may be hundreds of pages, sometimes I won't even get 10. YOUR mileage may vary.
the entire premise of what I'm saying is that you have to count ALL the costs including the cost of the printer. - if you're given or inherit a printer then you could take off the capital cost. you could choose to do that if you're renting a printer, this will make price per page appear cheaper,
for that 1st printer you can see a table below with those number of sheets average into cost per page over increaingly large print runs, it appears to get cheaper because you're begining to negate the cost of the printer, (i.e if you spend £300 and print 1 page, that's a very expensive printout, if you print 2 pages, the average cost just halved
the L550 I can't find for sale from a reputable UK source (I'm in the UK) I can find it on Epsons page listed as "printers for Africa" I can see it on Indian Amazon... overall, if I was a "western" customer I'd expect printing supplies hard to find(and therefore not suitable for an office)
costs may be a little out as I found the Epson WorkForce ET-4550 for sale on US sites and converted to UK for consistency.
the inks are difficult to find on sale for the epson. weirdly people are complaining about the costs, but direct from epson a 70ml (6500 pages) bottle costs nineteen bucks, that's as cheap as you;ll ever get ink I think! the downside being that this is basically self fill ink, so if you've ever had an issue refilling your own cartridges, (like spilling them etc) you can quickly find a $19 bottle of ink turns into a $300 new table or $1000 new carpet!
out of interest I worked out how my Xerox compares, avg price per page it is cheaper than the xerox right up to 22,800 pages where the epson starts to become a tenth of a penny cheaper per page...