DIY projects:
http://hanssummers.com/dummy.html
https://www.caddock.com/online_catalog/power/power.html
https://www.caddock.com/online_catalog/mrktg_lit/MP9000_Series.pdf
Objective: 500 W, need 10R 5x100 W / TO-247 case
https://eu.mouser.com/c/?q=684-MP9100
11.57 USD * 5 pcs = 57.85 USD / 500 W = 0.12 USD/W