This is an example parts list based on the work done by Johnny Lee on his PAPR design.  It's not well vetted at this time and needs thorough testing to ensure folks in different regions can bouth find the parts and use them succesfully, but gives a starting point on what it might cost to assemble your first DIY PAPR


Part Cost (USD $) Supplier Link
Arduino Nano  19 Amazon
 CPAP Mask 23   Amazon
 CPAP Hose  10  Amazon
 Brushless DC Blower 10 Amazon
 CBRN Filter 80  MIRASafety
 2 x 12V Battery  44  Amazon
 Goggles  13  Amazon
 Faceshield  15 Amazon
Total   215