Short answers, pulled from the story.
Nebula Science Fiction was founded and edited by Peter Hamilton, a young Scotsman who was 18 years old in 1952 when the first issue appeared. Hamilton used spare capacity at his parents' Glasgow printing house, Crownpoint Publications, to launch the magazine.
Nebula Science Fiction ran from Autumn 1952 to June 1959, ending with issue 41. It began on an irregular schedule before moving to a regular monthly run starting in January 1958.
Nebula Science Fiction published the first stories of Robert Silverberg, Brian Aldiss, and Bob Shaw, among others. Silverberg's debut story, "Gorgon Planet", was accepted by editor Peter Hamilton on the 11th of January 1954.
Nebula Science Fiction closed because South Africa and Australia imposed import controls on foreign periodicals at the end of the 1950s, eliminating markets that had accounted for roughly a third of the magazine's total circulation. UK excise duties added further financial strain, and Hamilton also faced personal health problems.
Hamilton reported a circulation of 40,000 in his September 1957 editorial. Only about a quarter of those sales were in the United Kingdom; roughly a third were in the United States, a quarter in Australia, and close to a tenth in South Africa.
Nebula initially paid 21 shillings (£1.05) per thousand words, with a bonus of £2 or £5 for the most popular story per issue. Hamilton later raised rates to as much as 2d (about 2.3 cents) per word for established authors, which matched the top American magazines of the time.