.222 Rem Mag
Is a fine sporting round for varmints, and would serve well at the target ranges. Sadly, the round was doomed by the US military when they adopted the .223 (5.56mm).
The original AR rifles tested were in .222 Remington, and the military decided on an energy requirement at 600 yards that the .222 just could not meet. Remington introduced the .222 Rem Mag in 1958, and it would have met the military requirement, but was not the round chosen. The 5.56mm round was adopted for the M16 rifle (it was a military developement), and later released to the public as the .223 Remington. The .222 Rem Mag will deliver about 100fps more than the .223 with top handloads. IMR 3031 is a good powder for this cartridge.
The .223 has become the popular round, and the .222 Rem Mag is fading away (in the US), due to the availability of surplus .223 ammo and brass, along with military style rifles. The original .222 Remington is also in decline, but still has a small following, as it is an excellent and accurate round for sporting use.
The .222 Rem, .222 Rem Mag, and .223 Rem are NOT interchangable. Do not use .222 or .223 ammo in your .222 Rem Mag rifle, cases will split due to excess headspace. This is a dangerous situation.
In your situation, and with prices the way you describe, I would strongly recommend you take up handloading. Midway has Remington brass in .222 Rem Mag for $237.99(US) per 1,000m plus shipping. Currently available, you can order online.