Tom's Toolery is a tool shop that only appeared in the episode "Overbooked."
SpongeBob was sent there by Mr. Krabs to purchase a drill to build his new telescope. The building is fairly large. It is unknown what the interior looks like, since in the only episode it has appeared in so far, "Overbooked," was closed for Porpoise Day. The sign for the Porpoise Day closure read "Dear valued Tom's Toolery customer, we are closed this week in observance of Porpoise Day. Please call again." Based on the name it can be implied that the founder's name and/or owner's name is Tom or he/she could be one of Tom's family members. It is known to have a motorized hex drill and presumably several motorized and manual tools along with screws, nuts, bolts, and other commonly used fasteners and gadgets.
"Tom's Toolery" is a parody of the phrase "Tom Foolery."