Seriously? All of you teachers think that the Staples company OWES you their loss-leader Back-to-School deals in unlimited quantities?
Admit that you enjoyed the sales when they produced tremendous savings.
Because the truth is that your school districts could negotiate "Extreme Discount" savings with school supplies distributors, easily, and much more economically than any retail chain store can. Examine the reasons why your school districts can't/wont do this. Explore alternatives, like wholesale purchasing through your unions, or a charitable school supplies drive through your PTA.
Finally, teach responsibility to these parents by *requiring* that students be supplied for their projects, and start giving Fs for any assignments left incomplete due to lack of supplies.
Direct them to Staples during Extreme Discount times, and to social services and church agencies that can help out. If there are still a couple of kids who can't get supplies after all that, you need to get the school counselor and the principal involved.
Or rather, it *was* your job, when it only cost you 45-50 bucks a year, and landing all those savings was a fun outing for you and your colleagues.