A few years ago, I spent most of my savings on The Lunar Chronicles by Marissa Meyer (Cinder, Scarlet, Cress, Winter, and Stars Above; I didn’t get Fairest), read them all, and loved them…though I didn’t reread them and sold them some time later.
And what was the first series you spent most of your savings on?
Purchased on my behalf? Lord of the RIngs
With my own money? Hitchhiker’s Guide to the Galaxy.
There are several other series I could argue were earlier but as their authors are still very much alive I’m erring on the side of caution with regards to finality. Never know when one might decide they have just a little more to say.