Clear lower M4 from Buyairsoft.ca. Not recommended, as for the price they have listed, you can get a much higher quality airsoft gun, providing you are of course of legal age.
Get age verified so you can find out where you can get better for the same price or lower.
The Tier One Tactical Operator
Tippmann Arms M4A1
KWA USP .45, KJW P226, KJW hi-cappa