Fundraising buttons are a fun way to raise funds for your community organization. There are plenty of companies who will make them to your own custom design. You can also just by the parts and make them yourself.
The most valuable buttons (or badges) are those with a fairly unique design (even a limited edition design). For schools that could be the school crest or logo. Likewise for sports clubs it's usually the logo with some type of slogan. Selling buttons for special days can also be a successful venture.
You can buy the buttons in bulk for between 20 and 50 cents. Depending on the desirability of the design you can sell them for anything between $1 and $15.
Have a look at the following companies to see if they have anything to suit your needs.
Badge A Minit
Dr Don's Buttons
Return from Fundraising Buttons to Merchandising