Who invented currency symbols? For instance where do the dollar $ and pound £ signs originate?
A pound sterling was originally worth a Roman pound of silver. The symbol £ derives from the Latin word for pound, libra.
The symbol $ is probably a modification of an 8, to represent 8 Spanish reales. Pieces of Eight were 8-real silver coins used in Spain and Spanish-speaking America and were worth just about a dollar each. They continued to be legal tender in the U.S. until 1857. They were sometimes cut into 8 wedges, each wedge being worth 12.5 cents. One of these wedges was called a bit. Hence, “shave and a haircut, two bits” (25 cents).
Cecil once did a column on this exact question. Here ya go: http://www.straightdope.com/classics/a3_178.html