Yeah -- thread has gone up sharply in the past few years!!
If you haven't yet discovered the Superior Threads website yet, it is probably time to do so:
https://www.superiorthreads.com/
There is another thread currently on the front page that talks about the company having been sold. I haven't bought any new products from them in the last 2 years, but I had no issues with them pre-sale.
Lots of good info and lots of threads at reasonable prices. Free shipping if you buy enough -- as you've found it usually doesn't take all that much any more, a couple of cones and some specials or "try me" threads. I first started buying direct from them when my friend got a long arm. We had a terrible time winding a decent bobbin with her machine and locally (a few years ago) Type M bobbins were just not really available in our area.
Some people swear by one brand or another. Poly threads have been developed which are much different than the threads of the 70s... no problems with ironing heat. Some people want to use all cotton thread, some donation groups (especially for preemies) require all cotton thread. If using all cotton, the typical favorites are made with Egyptian cotton (like King Tut) because of the long fibers. For metallic thread, I like Superior metallics line, it didn't kink, wasn't hard to use and was reasonably soft.
I used basic Coats and Clark threads for the first 30 or so years of my quilting back when I was told that the poly core was not advised because it would cut through the cotton fabric -- I never found that an issue, even after decades and lots of washing my seams stayed intact. As a result of the machine quilting/pre-wound bobbins, I did some experiments with my home machine and found that I liked So Fine thread just fine with my bobbin. Then I bought a huge box of So Fine cones from a professional long armer who decided she liked another thread better and was downsizing. Did some more tests and with a few adjustments, am now typically using it both top and bottom.