Glitch Status: Unpatched
[*]You must have enough money to buy the house you want for free in the first place.
[*]You must be within quick reach of a storage unit when approaching the seller of the house.
This glitch should work with every house. All you need to do is follow whoever sells the house until they're near some sort of storage unit you can deposit things in (e.g. chest, drawers, cupboard, etc.). When they're in a good location, I recommend saving your game so if you fail you can easily retry without any negative effects.
Talk to the NPC about buying the house. As soon as you get to the confirmation screen, when you say "I'll take it!" (paraphrasing), click on the speech option confirming your purchase and QUICKLY press whatever button on your console exits conversations. Again, from here you must QUICKLY click on the storage unit, browse to the MISC section and deposit your gold (the original amount should still be there if you were fast enough) in the storage. From here you should be able to talk to the NPC, receive your house key, and still withdraw 100% of your original gold out of where ever it was you stored it!