My 2 cents:
If you're around college students, Make friends with foreign students from the 3rd world. Eskimo's have some awesome ruderalis strains and some strains that I feel are not scientifically classified yet, they'll seem to be freaks of nature until you understand what you got and Asian will have strains I have never purchased from seed Co... Asian students come up with some 30'and up tall strains, sativa, and can get taller if you grow with bamboo, its a symbiotic thing... just bend em to the ground and cover mid-plant with soil, the plant will throw roots there and shoots will grow from the barried part of the plant. It hard to control mites at 30' and America's bug will feast on them. And if you meet the rite Mexicans and you speak some spanish they have some ol skool get high strains, freakish strong strains but not quite pure bloods. Also you'll need Great patients and you have to want it bad so if you're crazy like me go to country seed and feed stores and tell em you're racing homer pigeons and need pure hemp feed. 50 lb bags of inert seeds but 1% - 5% will germinate. Incidentally if your trying to get a grip breeding and understanding on DNA and genetic crosses and mutation try breeding pigeons. Pigeon breeders are some of the best geneticist that I know and have great insight on zygosity. Now back to finding pure strain. Some of my best finds have been from small bags of bird feed from super markets that have cannabis seed mix seeds. If you dont want to go thru this pain try World of Seeds, not bad, and about as close as Ive gotten to some ol skool strain but far from purity.
It will help 10 fold to have mastered seed "embryo rescue". Dipped inert seeds that are supposedly inert have mostly dead apical root tips most of the time, dont worry fellow grower the embryo is still alive and if you have "Rescue" skills that are stellar you can save the baby. But all this is lots of work so if you can get access to seed chipper you can DNA each seed to know which ones have what you're looking for before you put 100's of hours of work into a worthless non-heirloom. Until you master embryo rescue do not try splitting the embryo's however once you're able to split embryo's you'll accomplish years of breeding in your 1st propagation. These skill will serve you well if you fortunate enough to handed 1980 or older seeds as after a few years all strain start loosing vigor and will be very hard to germinate if your not at the top of grow game.
So if you dont like spending 1000's of hours of study and breeding pigeons and playing with test tubes, one of the best ways to understand breeding, then you can chuck some pollen at World of Seeds strains.
panama
old seeds are hard to germ
save and label your seeds