š” Not automatically. Being a 501(c)(3) nonprofit doesn't by itself make your purchases sales-tax exempt. It depends on the state, and you usually have to apply for it.
Why it's not automatic
Sales tax exemption is granted state by state, separately from federal 501(c)(3) status. Some states offer it to nonprofits, some don't, and the rules and paperwork vary in each state that does.
How to pursue it
If you want to claim sales tax exemption for purchases in a specific state, email hcb@hackclub.com and let us know which state. We can tell you what's possible and help with the paperwork.
What about selling things?
This article is about sales tax on what your organization buys. Selling is different: HCB organizations can't sell merch or products, because collecting and reporting sales tax on sales isn't something fiscally sponsored projects can take on. See Can I sell merch or products through HCB?