Paper is the foundation of many craft projects. Whether you're a serious scrapbooker, into origami or just like to make your own personalized greeting cards, a good supply of paper is a must. Don't limit yourself; butcher paper, printer paper, and construction paper are great basic craft materials. Check out the dollar store, and keep an eye out for sales to stock up and increase the variety of your supply.
Some types of glue work better than others for specific applications. The basic white glue we all remember from elementary school is a good starting place. A bag of glue dots is nice to have on hand for more delicate applications, while glue sticks and clear glues are useful in a wide variety of projects.
Keeping a collection of tools just for crafting is a good idea. There's nothing worse than trying to cut fabric, plastic or paper with dull scissors or blades. Store your crafting tools with your supplies. As your crafting interests evolve, add the appropriate tools. Taking good care of tools maximizes their lifespans.
You can use stamps and stickers for an infinite variety of projects, and most are inexpensive. Kids love them and will use them to decorate and personalize everything from book covers to bulletin boards. Add to your supply whenever you see a sale or just happen to come across something new and different that you know will be a hit with the kids.
Nothing is more frustrating than discovering you don't have the right color of marker or pen when you're ready to add that final touch to a card or scrapbook page. These craft supplies do double duty with the kids for school projects, so keep a nice variety on hand.