The true cost of owning a printer is not the original purchase price. It is the cost per page for printing over the lifetime of the printer that really tells the tale. If the prints are comparable in price and functionality, the cost per page of black and white and the cost per page of color printing is the factor you need to examine closely.
The main difference between the bubble jet and ink jet is in the way the ink is 'pumped' onto the paper. In the bubble jet printer, tiny heaters create heat, and this heat vaporizes the ink solvent to create a bubble. As the bubble expands, some of the ink is pushed out of a nozzle onto the paper. When the bubble "pops" (collapses), and a vacuum is created. This pulls more ink into the print head from the cartridge.
The ink jet printer has a tiny crystal located at the back of the ink reservoir of each nozzle. The crystal receives a tiny electric charge that causes it to sort of do the hula. When the crystal moves, it forces a tiny amount of ink out of the nozzle. When it moves back, it pulls more ink into the reservoir to replace the ink pumped out. Given the size of the droplets given above, the bubbles and the movement of the crystal are very, VERY small. Watch your printer move when you print something. It's truly amazing to see how the text and/or images are printed when you consider the size of each droplet and the speed of movement.