They are about $50 from my search which is about 5x more than the plantower pm2.5 sensors. There is a big difference in documentation and that issue with the new MCU on the plantower units is concerning since they all have the same markings and housing when purchased.
At volume, the SPS30 gets down to ~$30 a piece. Their newest sensors (SEN5X) offer similar specs, and are about $25 per single unit, or $15 a piece at volume for the cheapest variant. The more expensive variant include integrated T/RH monitoring, which is very handy for humidity corrections for this type of PM2.5 sensing.
