Sims 3 is currently in the Sweet Spot. All expansions are available and if you look around, you will find them all for prices between 5 USD and 10 USD. Given the sheer number of stuff packs, worlds and extensions it will still be a very expansive game if you get them all, but in my humble opinion it is worth it, because, as an avid gamer, it is also the game I spent most hours with.
But if you finally have it all, you will face another problem. Each of the so called store worlds specializes and so lacks the features until you create or import specialized buildings to your favorite world. Thankfully there is a strong community for the creation of custom content for the Sims games, like Mod The Sims and The Sims Resource where some creative spirits have created more wholesome worlds. One of my personal favorites is Storybrook from My Sim Realty.
But than came the Store World of Roaring Hights and I have to say I loved it (even though I didn't buy it until it was out in stores and, again available for a reduced price). But as much as I liked it, it pretty quick become boring gameplaywise, because, again, I had to place a lot of spezialized buildings and change some of the already build ones to get a nice park for seasonal festivities, pubs and clubs and other places, like a horse farm (I really wanted to have horses for once in my game). And because Roaring Hights has such a special look consisting of Art Deco and Mediterranean Revival, I mostly had to build them from scratch.
Also my favorite family was actually a bunch of Mermaids and at home in Isla Paradiso, which also is one of my favorite worlds, inherent stuttering not included. Roaring hights, despite it's many waterways, didn't really play well with the features of the Island Paradise Extension So I quickly formed the idea to build a world that caters to all I like about Roaring Hights and Isla Paradiso that also includes every gameplay from the other extensions, including some of the more "gamy" elements enabled by World Adventures and Isla Paradiso where you can go on "quests".
Thus the (hobby-)project Sagan Harbour was born and has now reached a level where I can proudly present my ongoing work.