In a large stock pot over medium heat stir together the popcorn kernels, sugar, and oil until well combined. Cover and swirl the mixture around until the kernels start popping. Continue to swirl and cook until there are 2 to 3 seconds between pops — this only takes a minute or two.
Immediately turn the popcorn out into a large bowl and sprinkle with salt. Let cool completely.
Toss the cooled popcorn with the M&Ms®, raisins and other mix-ins, as desired. Store in glass quart jars and tie decoratively with ribbon. Makes excellent gifts.