Take an hour or two to figure out your needs (necessities) and wants (luxuries). Then organize the list from most to least important. Ask a parent or another trusted adult if you need some help.
Warning: Don’t confuse wants with needs. For example, you may need a new pair of soccer shoes (if you play soccer, shoes are an essential expense), but that expensive pair with the fancy logo is a want. The basic, black shoes with the white stripes (for a fraction of the cost) will do.