For a letter of no more than 3 to 6 pages, just one first-class stamp.
just 1
44 cents
Florida is in the US...
It will cost you 98 cents for an ordinary up to 1-ounce letter.
This depends only on the weight of the letter. If it is under 13oz you can send it anywhere in the country with 1 first class stamp.
about $1.56 for 5onces. go here to see all the options http://postcalc.usps.gov/
It costs $0.98 to send a letter to London.... no special stamp needed since they now all go via air-mail.
Only one stamp is needed to send a letter from state to state within the United States. The current cost of a stamp is 49 cents.
It depends entirely on the type of aircraft and how it is flown.
5.7 and a 49 on your ACT
Your local police can assist you with what is needed.
To the best of my knowledge, no place exists in the USA where you can start a fleamarket without a permit. Generally a business permit is required, and a sales tax license. Some places may require a special permit for flea markets. This is a vague answer, but it can be improved upon by others.