* Hardware store: This is the most common place to buy nails and hammers, so a hardware store employee sells them.
* Building supply store: Similar to a hardware store, but often larger and carrying a wider range of construction materials.
* Retailer: A general term for anyone who sells goods to consumers.
* Vendor: A person or company offering something for sale.
* Specialty tool store: Some stores specialize in tools, and they would sell nails and hammers.
Ultimately, you would most likely call the person helping you "the hardware store employee" or simply ask "Do you work here?"