All good responses and leaving precious little to add. I have several friends who are handloaders and when we embark on an adventure, as you are, we share our resources and invest only in what one of us doesn't have, and then share what is left over.
Like primers. I'm sorry, but I have found that over time, primers go bang pretty well and I've never lost an animal or a match trophy because of a primer. Let's say you do invest in 5 different brands of primers to go with the other brands that you an/or your buddies already have, and you find one brand that does make a difference in your group. All is well. SAVE the one brand for your teeny tiny groups, and use the rest for hunting, plinking popcans, teaching youngsters, etc, or use them to swap with others for whatever. No need to throw anything away. Likewise with powder and bullets. It all goes bang and it all goes downrange. Next year you may have a different adventure to embark upon and it may be "just what you need". One of us may be in your area and willing to swap stuff with you to get started.
I'm in North Idaho if that helps at all.
Regards,
Sweetwater