If you go to
this catalog and look around, you can see the items -- the aerial views will show you how they actually look. And there's a garden section.
Cream rugs, funky lime tables, tall table lamps, blue or red bean bags, violet shelf units, purple wardrobes, and royal oak beds are usually cheap and plentiful. Sand sculptures are good space fillers too. Kitchens can be very pricey, if you want a unified look. If you want a cheap bathroom, try for the spooky stuff, and spooky is usually a good theme for a bedroom too. Dung and stone furniture sets are usually really cheap too. If you want a theme room with, say, all Haunted Fairground and Dark Nova items, you might end up at the Trading Post more often than the Shop Wizard...