I am a sneaky boi in nerf wars and i need to know, What is the best AND CHEAPEST sniper foam dart gun that has rails and a barrel attachment point under $20?
OP asked for "best foam dart gun"... "for a sniper".
"Blowgun" is still a gun.
"Throwing knife" is pretty far off-topic, and just because a sniper could use it, it's no more a "sniper weapon" than a wire-guided TOW missile is, because technically a sniper could use that too.