Removing old tile can be a labor intensive project, but it pays to do it yourself if you are trying to save money.
One useful tool is a floor scraper, which features a steel head that is angled for stripping off flooring layers. This is about the size of a broom and will set you back about 20 bucks from the hardware store, though it always pays to check Harbor Freight if you have one nearby. These babies make it a breeze to free up large areas of tile from the adhesive, which would otherwise require a lot more effort using a hand chisel. But you will still want a handheld chisel for certain areas. Other useful tools include a paint scraper, a hammer, leather work gloves, safety glasses, a dust mask and some kind of sheet or drop-cloth.
If you are lucky, your tiles were set using mastic and a floor scraper is usually all that is required to quickly free the tiles. However, if mortar was used instead, you will need to break up the tile, and all that safety equipment will come in handy. Use the hammer to bust up the tiles from the center. The glasses will prevent shards from hitting your eyes, the dust mask will protect your lungs, and a sheet dropped over the tile before breaking will prevent pieces from scattering all over. Be sure to use gloves, as the shards can be quite sharp.
Next, use your chisel to remove any remaining pieces as well as the grout. Once a few tiles are removed this way, you should have enough room to maneuver the floor scraper. Now you can break up multiple tiles at once with your hammer and then scrape them out en masse. If the mortar is not coming straight away, hammer directly on it to break it up and dislodge it from the underlayer. If you are having trouble with stuck adhesive, a heat gun or even a hairdryer can help loosen it to where a putty knife can be used.