One of my favorite finds at The Dollar Store are these little colored glass gem stones. (If you google it, that's what they are called.) I found bags of these on the isle that contains the house decorating items. These glass stones are used in vases and glass containers for decoration and to hold fake flowers. But I love using them in my classroom! They come in different sizes and colors and are also available at craft stores.
Just recently, my students were comparing numbers. I have a large 100s chart on the wall for my kids to use as a reference, but one particular child was still struggling. For him I provided a personal 100s chart and some colored gem stones. He could place the stones on the numbers he was comparing and could easily see which one was greater. Worked perfectly and he loved it! Of course, these discs come in handy for other math activities as well. In addition, I have used them during our reading group activities. My students love to place them on top of words in their readers to highlight. They are great because the kids can still see the words. Since they come in different colors I can tell my students to use green to find short a words, blue for short o, etc... They really come in handy!