If you're in search of a cheap red dot sight with a wide field of view, the Delta Armory 1x30 Red Dot Sight is exactly that. Boasting an integral 20mm Picatinny mount, 5 brightness settings with either a red or green dot and a whopping 30mm objective lens, this red dot sight is ready to mount and cheap as chips, even packaged with a CR2032 3V Button cell to get you up and running straight out of the box.
 
Features
Aluminium construction - Steel mounting bolts, alloy mount
Red dot sight - Great for fast target acquisition and low-light scenarios
Integral 20mm Picatinny rail mount - Ready to mount to any Airsoft gun with a 20mm top rail
30mm Objective lens - Wide field of view, great for avoiding "tunnel vision"
Low profile mount - Requires a rail riser for optimal height on M4/AR-15 AEGs
5 Brightness settings - Adjust the brightness for low light or bright conditions
Red or Green reticle colour options - Choose the clearest for your environment
Windage and elevation adjustable - Capped turrets, unscrew the cap and use a flathead screwdriver
Battery compartment inside the illumination adjustment turret - Unscrew the top cap to access
Battery: 1x CR2032 3V Button Cell (included)