Ebay offers SupplyAid 3-Ply Face Mask 50-Pack for $4.48 (reg $39.99) after code with free shipping.

Apply Code: SJMEMORIAL25

Product Description:
Protect yourself from airborne dust, pollen and other allergens with 3 layers of protection! Disposable Face Masks from SupplyAID protect against fog, smog, air pollution, fine dust + droplets and other airborne particles. The disposable design is perfect for all-day wear. The 3-layer mask features a non-abrasive inner layer and outer layer made from breathable, non-woven fabric, and an antibacterial filter middle layer. The elastics sit comfortably on the ears, and the moldable nose piece ensures a secure fit on the face to prevent shifting during movement. Ideal for daily use at home and at work, travel, or trips to the supermarket and gym, this 50-pack of masks help prevent the spread of germs and protect against airborne dust and allergens. Count on SupplyAID and the SupplyAID family of products: The right health + wellness essentials, right away. 
Instructions for use:

•  Gently position the mask to the front of the face
•  Adjust elastics over ears
•  Mold nose piece to fit securely around nose bridge
•  Pull the bottom of the mask down over the chin