First you'd need to look for which companies can service your area. In mine I'm limited to AT&T and Cox. That's it. Verizon's FiOS and Cox have good promos; same thing with AT&T, and you can always compare promos from other companies and have either your current company match it (telling them upfront that you're considering leaving because of that) or you might get other deals from other companies if you don't say 'yes' on the first call (when I set things up I ended up with no installation fee, 300 dollars in rewards cards, and HBO for a year).
Also, if you live in an apartment complex, you can see if the (usually free) WiFi from the leasing office reaches your apartment, or negotiate with neighbors to 'split' the cost (just bear in mind the speed you're getting and how many people would be using it, on top of possible repeaters that might need adding if the signal doesn't reach one apartment or the other; also it's not illegal to the best of my knowledge, but it IS frowned upon...)