That's the TSSOP version, while the DIP is $0.92:

https://www.digikey.com/en/products/detail/microchip-technol...

I'd prefer even the SOIC version which is $0.69 if I'm soldering it:

https://www.digikey.com/en/products/detail/microchip-technol...

but the author used the DIP in a holder/socket on the perfboard.