The Sims 3
50 Achievements
1,000
30-35h
Movin' On Up
Moved into a new home.
40
How to unlock the Movin' On Up achievement in The Sims 3 - Definitive Guide
You click on you Character
You select your cellphone
Scroll through the options
You will find an option that says move.
That allows you to move into a new house and also you can move into a new house after you sell all the furnitures from the first house.
If you dont really want to move and you doing it only for the achievement , it would be wise to save it before you move. After you move and the achievement unlocks just exit without saving the game and load your old save to continue with your first house .
A new option appears under "friendly" interactions to move in. Select that option, move your sim to the new sim's house, then BAM....achievement unlocked.
Just for simplicity towards other achievements, I would recommend finding a sim of the opposite sex and using some romantic interactions. When you become housemates, and thus control the new sim, it is really easy to get the relationship achievements such as First Kiss, Marriage, and of course make "Woo Hoo!"
Keep in mind that any Sims left behind will be deleted unfortunately. For some reason, the console version does not allow you to create multiple families.
Once you either get enough money or you get married/have a child the game will tell you that you're able to move out and buy a new house. To buy a new house select your sim and go to his/her cell phone. Scroll down until you see move and click it. The cheapest house besides the one you start out in is the one on 72 Erin Lane and it costs about $13,000. Once you buy it you'll need to pick the new people who will be moving into your new household. Once you pick them then click on move in and bam! trophy.
When you have collected a decent amount of money around $15,000 - $20,000, simply select your computer or cell phone and select "move". A pop up will come up asking you which Sims are moving, select the Sims you want to move with you. Then move out of you first home by selecting a new house from the town map which you can afford. You can always save before moving and get the achievement and then reload the previous saved game if you don't want to move.