First of all, find a cheaply furnished home (with maximum 3-star furniture), and best of all a house around 10,000 gold. Then for the easy way: kill the owner, wait for a new one to respawn and kill that one too. Repeat this process about five times and the price will have dropped greatly. Buy "Luxury" furniture (the best place for that is the Bowerstone Market shop, World of Chairs) and replace every piece of furniture in the house with the "Luxury" furniture. By killing owners the economy can drop (if not, don't bother killing the entire town) and by decorating it the economy will rise again, and the value of the furniture will give you the double value.
Another way to earn this achievement without committing any crimes is to find the house in Bowerstone Market named Wraithlodge (It is the first house on the right, up the stairs when you are heading towards Bowerstone Old Town). It is a one-star rated house and is bought fairly cheap compared to most houses you can purchase in Bowerstone. Next, redecorate with Luxury furniture from the nearby furniture store and the value of this ill-named home will triple in value! (All without killing the owner to drop its already low price, placing a bounty on your head.)