[cprecioso]

Maybe somebody can help me find the $20 one, but the one I can see is $460

https://estore.st.com/en/stm32h753i-eval2-cpn.html

[mkeeter]

Look for the "Nucleo" boards rather than full-fledged eval kits, e.g. https://www.st.com/en/evaluation-tools/nucleo-h743zi.html is $26.

[taink]

I don't know if this is a reputable source in any way but a quick search shows this: https://www2.mouser.com/c/?processor%20series=STM32H753