I had to save up for it, but I’ve always slept poorly and wanted to go all in on the new bedding. Maybe I’m crazy, but I think it was worth the money.

100 seems like a lot for just a pillow. However, you use it every night and it helps you waking up without back or neck pain. So, investing 100 dollars into something you use 1/3 of every day seems like it's basically nothing. My pillow costed almost 200 euros, my matrass was 1800. I've had it for 10 years, so it costed me 2000/3650= ~0.548 per night, 7 to 8 hours per day. Almost 55 cents for proper back and neck support, so I don't wake up stiff and sour. The longer I use it, the cheaper it becomes, but I think in a year or two I'll buy a new set so I'll be sleeping like a princess for another 10 to 12 years.

Plot twist: learning to sleep without a pillow is even better for your back and neck. So, there's your cheap option.

https://www.ikea.com/us/en/p/klubbsporre-ergonomic-pillow-side-back-sleeper-80446101/

I use this one. It's pretty great I think

You don't need to pay quite that much to get one, but investing in a nice, expensive pillow really upgraded my sleep quality dramatically. I won't even let my houseguests use cheap pillows anymore. The difference is just too dramatic.