I babysat starting at 12, so I had some disposable income. And zines were relatively cheap in the late sixties, early seventies, before offset replaced mimeo printing. A lot went for 50 cents though the postage costs often doubled the price of a package of zines. By the early 80s zines were up to 20$ for some, even before postage. And most of the individuality and creativity had gone. A lot was was mediocre slash by then, and I suspect written to make a quick buck due to the high prices, wide margins etc. As I left home, paid rent, then bought a house, zine purchases were generally a once or twice yearly splurge since most editors scheduled their zines to come out at cons, and being in MD, there was ShoreLeave and Clippercon, etc., where I would go and buy zines. Still buying zines was a worrisome thing, since disposable income was always scarce, and often you had to prepay. Sometimes waiting years for the zine to finally be produced. And if you didn't prepay, it would often be sold out.
I have heard a lot of older fans just trashing their zines, because they can't be bothered with selling them, and they may not want their relatives to have to deal with them. It can be sad.
Re the "scarred for life" comments, that was one of the things that shocked me when I decided to put some of my fiction up on ffnet. I got comments accusing me of "triggering" them. That I think would have been unheard of back in the 60s, 70s, when I think most editors thought if you were buying a Trek zine, (apart from those that required an age statement which came later, I think) you were a SF fan, not a hothouse flower.
I have most of the ones you listed. I knew Marion McChesney, who published some of them, if I remember right. I remember The Sourdani Journal - that was an unusual one. This winter, when I am snowed in, I'll have to drag a few of those two dozen plastic tubs of zines up to the house and go through them.
I think you mentioned In A different reality. Did you ever read any of Suzanne Sizemore's pro fiction - not Star Trek. It was mostly vampire related. I am not a vampire genre fan, but tried them. One of them to me had a very Pride and Prejudice feel and I think was the best of them -- Companions, laws of the blood, book 3. Sad that she is gone. Gayle Freyar (probably spelling her name wrong) she wrote some pro fiction as well in the romance genre.
Interphase certainly was a great zine. And Metamorphosis. So many great zines. With unbelievably great stories that could leave one in shreds. I certainly spent a lot of time pursuing and reading those things (and got knows how much disposable income!)