Its a DLC scam. Like 1000 bucks worth, and rarely on sale.
The game is not too bad. They removed a few features from the gameplay as compared to Sims 3, but its not a lite version or anything.
Also, it is considerably more stable and runs smoother. They fixed a crapload of bugs and you dont get the hiccups and random crashes from Sims 3. Nor does the game chug along after you've put a lot of time into it and made multiple houses and retired multiple family members.
Try to find the base version on sale, play it for a while, you'll know if you like it or not. Then decide how badly you want the DLC packages.