Art develops small motor skills, intelligence and creativity. You almost can't have too many art supplies, but they don't have to be expensive. I mean the things you have around your house that don't look artistic to you, but do look artistic to children. Just collect a big box of the stuff and set it with your supplies. Story-telling materials are also important.
Puppets are easy and inexpensive to make.
I have a number of links in my language arts listings that tell you how to make simple flannel boards. Add some dress-up materials from your closet or a yard sale, with a heavy emphasis on hats and jewelry. You can make simple acting props like crowns yourself. You'll need books, but you can borrow the ones your child already has. If you buy a new book, save it for school the first time you read it.