Dremel MM500 1/8-Inch Multi-Max Carbide Grout Blade [1] $7.33

Dremel MM500 1/8-Inch Multi-Max Carbide Grout Blade for $7.33, all-time low according to Keepa price tracker (180-day avg @ ~$22).
https://smile.amazon.com/gp/product/B001GNC8TG/