At any Dollar General Store.
the muji store
Spirit Halloween the store
A business can get engraved pens to give their employees as gifts at a store that design and sell engraved pens. The best companies that sell engraved pens would be Pens-R-Us and Cross.
12 pens @ 12¢ each = 144¢ = $1.44
Any office supply store will carry at least a few fountain pens. You may also buy Fountain Pens online.
five below prank section
Michaels Arts and Crafts Store
These gag pens mostly use "AAA" size cells. They are, after all, "pens" as in the writing instrument. The triple A cell will fit inside the body of the pen and it won't look too "fat" to alert a potential "victim" to the prank. Original answer by QuirkyquantummechanicSome shock pens use mercury batteries for size because they need to fit it in.
Gimbels department store in New York was one of the first to promote the sale of ballpoint pens in 1945.
Walmart, Target, any store that sells supplies.
Michael's craft store