I still remember the time I seen Dell selling an entry-level printer for Â£9. Only problem here is that I remember people complaining about the Â£27 ink cartridges it took, until someone said something like "Who cares! Buy a new printer each time the ink runs out :)" and another comment saying "I bought 5 printers to save on postage, but I'll rob the ink of the other 4. 3 will go straight to the recycling centre and keep one as a spare." A few weeks later, the Dell offer ended and Inkjet printer prices returned to roughly the cost of a full set of consumables to end the loophole.
With the Kindle Fire, I think Amazon is careful here to prevent customers exploiting such a loophole, e.g. not giving away vouchers, free subscription, etc. that add up to more han the price of the Kindle Fire.