Second, purchase resources which can be used by all or a large number of your families. Third, choose resources that supplement core curriculum texts or unit studies. These items will in most cases only be used for a short period of time and then returned for others to use. Fourth, try purchasing big-ticket items such as math manipulatives. Purchasing new, unused resources is also a good idea.
New resources have broader appeal and they last longer.
Fifth, keep a balance in the materials that you purchase. Consider buying materials that appeal to a broad range of needs. An excellent idea to achieve broad appeal and maximize funds would be to purchase the whole set of convention tapes from your state's home school organization. The set will cover a diversity of topics and you'll only have to pay around two hundred dollars. The funding issue can be a call back to reality.