Answer:
Unfortunately, with Sims 1 being the first game, it doesn't actually have downloadble things. The Sims 2 and 3 do however.
While The Sims 1 is getting on a bit, after all we are up to Sims 3, there are still many of us who still love the "old skool" version. There are literally hundreds of sites you can download custom content from. Ive downloaded lots (as in hundreds) of shops objects, cafe objects, home objects, skins, walls, floors and even a Womens Health Clinic. Most links are no longer working these days but there are still alot around that have their creations available for free. Alot have gone onto Yahoo Groups so look there too. Try Parsimonious for really beautiful shop objects and Around The Sims for restaurants and shops. There are some "adult" objects too, on a couple of sites, but best left alone I think. They are very graphic! By far the most extensive collection of downloable things for The Sims in any version (1 2 and 3) is The Sims Resource. The Sims 1 stuff is free you just have to join up. Enjoy :)