As others have noted, during the 1980s and to a lesser extent, in my experience, up to the mid-1990s every LCS and comic book convention I frequented and mail order dealers I purchased from graded almost every back issue comic book and magazine, with some difference between dealers, from roughly VF (very often, F/VF) up the "all-encompassing" NM. Having said that, I, like others that have replied, was a NM purchaser but for the expensive issues I had to settle for the highest grading copies that I could afford and, thankfully, I was able to very often place them on "lay-away."
As concerns the prices I wanted to pay, I had a list, hand written, that I always carried with me listing the back issues I wanted, including, of course, grade and OPG value. I likely updated that list 500 plus times over many years. I often paid more than what I wanted to because, well, the dealer wanted more $. In hindsight, I'm very glad I paid more than my list "said."