Do Store Worlds Go on Sale?

Katofhyrule12​  The worlds you can only buy with SimPoints are never on sale, with the exception of Sunlit Tides, which is on the Daily Deal rotation.  Only the standard version goes on sale, but the venue does too, so it's cheaper to buy both on sale than the Gold version at full price.

Store worlds you can buy with real money. do go on sale, typically when other Sims 3 content is on sale.  The list is Barnacle Bay, Dragon Valley, Monte Vista, Roaring Heights, and the worlds bundle that includes MV and Hidden Springs.

If you don't want to pay full price, the other option is the Make Me an Offer tool, which offers random items you don't own for random discounts.  It's tedious to use, and often enough, a given offer includes a set you wouldn't want or that's a lot cheaper to buy through the Daily Deal and Complete Your Set, canceling out most of the discount; or the discount itself isn't significant enough.  But if you're patient, you'll likely eventually get a good offer.  It took me a number of months, but less than a year, to get all the worlds minus Hidden Springs (which I bought as part of the bundle) at various discounted prices.

I will say though that the MMAO discounts are not all that high, only rarely over 50%.  So if you're looking for something in that range, you might be waiting a very long time.