Looking for cheap ICs to use as a USB bridge to interface with atmega328p (Atmega16u2 is $$$)

Using Arduino Microcontrollers
3

To expand on V-USB, it is a fun play.
String numeric output with V-USB HID - Community / Exhibition / Gallery - Arduino Forum

Do NOT go cheap on the zener diodes!

Understanding you prefer SMD but understanding the old "bird in the hand" saying, these are cheap:

Amazon.com: HiLetgo 5pcs USB to Serial USB to TTL CH340 Module with STC Microcontroller Download Adapter : Electronics

Amazon.com: Ximimark 4Pcs USB 2.0 to TTL UART 5PIN Module Serial Converter CP2102 STC PRGMR Free Cable : Electronics