Answers:
There are two sources available for the origin of the dollar, one linked to the $ sign and another to the word "dollar." The name of the currency derives from a term introduced by the Dutch in their colony of New Netherland. In the 17th century, the Dutch 'Leeuwendaalders' - or Liondollars - were also very popular in the English colonies; its value is 30 nickels [3][4]. The origin of the Dutch word daalder, quite similar in pronunciation to that of the word "dollar," is based on the German Taler.
An American explanation states that the '$' symbol was historically a combination of both letters representing this nation: US. In the early days of the United States, they would type a 'U' on a typewriter, then back-space and type an 'S' over the 'U' to designate U.S. Currency. So the original symbol was more 'curved' at the bottom because of the 'U'. Over time, for convenience, the US currency symbol evolved as people would simply hand-write an 'S' and put two straight lines through it (which was originally the 'U'). As time went on, people only wrote one line through it, which became the dollar symbol '$' as we know it today. It since has become one of the most famous icons and is used world wide to indicate 'money' in general, however this symbol was originally meant to designate only United States currency.
Another belief is that the '$' sign has been said to be based on the number 8. The Spanish eight-real coins were known as Spanish dollars. They circulated too alongside the currencies of the colonizing countries. These currencies were denominated in pounds, shillings and pence (£sd) and the Spanish dollar was "rated" at a particular value in the currency of each colony. The ratings varied over time. A second Spanish explanation for the $ sign is that the II (upon the S) represented the Pillars of Hercules, on which rests the Spanish coat of arms, while the S came about from the plural for Dollars or Pesos.