I bought too many masks (I did not know that my friend had already bought me some masks when I bought mine). I bought my masks at $35 per box (with 50 masks) from this company:
They do not have individual packing for each mask. However, I have tested out the masks and they should be of good quality (ie. water goblets are formed on the surface of the middle layer; and I could not see through the middle layer when holding against my ceiling light).
I wonder if any of you still need more masks. I am willing to sell them at $30 per box (I have 9 boxes of stock which I can spare). I can also show you the receipt from the company. I bought them on 29 April.
If any of you is interested, pls PM me. I prefer to trade along the MTR line.