There is one way that you can buy a house and it's upgrades without that you need to pay anything! first what you need to do is:

If we say that you want Breezehome in Whiterun you go to dragonsreach and the wait for the jarls steward to stand in his usual place. Then behind him further away there is a dresser. Run against the steward until he simply is forced to back and continue to do it until he stands next to the dresser and then say that you want to buy a house and then click on: "i'll take it" right after that back of from the menu so that he just continues to talk and then as fast as you can you open the dresser. Put all of your Money in that dresser before he has finished speaking. After you do that he can't take the money. you can talk to him again to make him stay still so that you can buy the upgrades too. Simply repeat this until your finished and then just take back your money from the dresser and voila! A free house!

PS: Some of the stewards like in Markarth or Windhelm is a long way from a dresser, but you can go to like a "barrel" too or you can just wait for him to sleep. In their room they need to have something;D

Have any questions? Just ask!