When I went up to Cambridge, one of the first societies I joined was the Science Fiction Book Club. And each Wednesday afternoon, I bicycled to the college room where it was kept, to return a rucksack full of books, and borrow another rucksack full.
Before that, I got my fix partly from the Stamford Hill, Tottenham and Hackney public libraries, and partly from a Saturday market stall that sold old SF magazines for sixpence. My favourite was Analog, but IF was one of the good ones.
So imagine my delight when I located a treasure trove of 176 issues of IF. They are PDF files, and are the entirety of the magazine from start to finish. You can download them for free, here.
I downloaded them, put them onto my iPad (ladysolly's old iPad 1 which I inherited) and they make excellent reading, using the Kindle app as the reader.