Sims 3 next sale?

@itsdevinboi  Steam probably won't have a Sims 3 sale for a couple of months, but you could always make an account now and put the game on your wishlist—I think you'll get an email alert when it's on sale.  Once you buy the game, you login to Steam, go to your library, click on the Sims 3 entry, then the cog wheel (in the red box, below), then Manage, then CD Keys.  You'll see a 20-character code for each pack you've bought, and another one for the base game, if you ever want to register your second copy.

To register the codes, open your Origin game library, click Add a Game in the upper right corner, then input each code.  Alternately, you can register the codes on the old Sims 3 store site (store.thesims3.com), which still works quite well.  Just make sure you're using the same account that has your Origin games.  You'll be able to tell because your existing packs will show in the left panel on your own page.  In either case, the packs should appear in your Origin game library; if they don't, clear Origin's cache and look again.

Please keep in mind that you can only access the Steam codes from a computer running Windows.  You don't have to have the game installed, just sign in and grab them.

By the way, I don't know what packs you already own, but there are occasionally bundles that bring the cost down even further.  I bought the base game, Pets, Seasons, and Generations together for $7.50 (normally $30), and I've seen a bundle with six stuff packs for something like $21.  If Steam itself doesn't show you the bundles, a google search ("Sims 3 bundle Steam" or similar) will turn up the direct links.