I checked Digi-Key through RPiLocator and they report several thousand units in stock each of the Raspberry Pi 4 2GB at $45 and of the Raspberry Pi 3B+ 1GB at $35: https://rpilocator.com/?vendor=digikeyus

For those unfamiliar with them, Digi-Key is a electronic components supplier to manufacturers but they also sell to individuals. Their stock count should be accurate.

Every single official US retailer has units available for MSRP. Where are you looking? Which model are you looking at?

Are you talking about the Pi5 4GB which is $60? We are talking about the Pi4 2GB which is $45. For many things, the cheaper, older version is fine.

Look harder? They're available at a number of retailers, and if you're in the US, Adafruit is recommended - but I wouldn't pay more than $35 + shipping in any case. There are a couple of dozen online retailers here with the 4B 1GB:

https://rpilocator.com/?cat=PI4