Not counting cap guns and water pistols, the least expensive firearm is likely to be a single shot .22 rifle, or a single shot shotgun. Plain simple versions may sell for $100-125 new. Older, USED handguns in .22 or .32 caliber may be $50 and up- but may be of poor quality and reliability. In their 1896 catalogue, Sears had the cheapest I have seen- the 69 cent revolver. However, that was over 100 years ago, and inflation has set in.
If your talking about what is the most powerful airsoft gun? Then my guess would be a sniper rifle. The WELL L96 sniper rifle is said to be the most powerful on the market. It shoots 500 feet per second and is also very accurate.
Note that "least expensive" is two words. The least expensive item in our restaurant is the white rice.
Rocketfish RF-QX3 appears to be the least expensive set of Bluetooth Headphones on the market with a manufacturer retail price of only nine dollars. Bluetooth Headphones are something that usually you should purchase not cheaply because you want good sound quality and comfort of wear.
Formica or laminate it is the least expensive.
A caulking gun.
The least expensive car is probably the Tata Nano.
The least expensive mode of transportation is by water. It is fuel efficient, less polluting and the safest. It is also the least expensive to move cargo.
very expensive very expensive
The black market
bananas are the least expensive and most popular fruit.
The COBRA DIGITAL HDVC5100 5.0 Megapixel 3-in-1 HD Digital Video Camera is the cheapest i can find.
I own one and have Michelin tires on it, with which I am very happy. They may not be the least expensive tires on the market but you get what you pay for.