True night vision scopes that are worth anything will run you several thousand dollars on the low end. Those using phosphorous are true night vision and use ambient light. The other option are thermal scopes, which do not use ambient light, but rather heat signature. As a general rule, thermal scopes will run more $$ than night vision scopes.
Best entry level option is a night vision monocular worn on the head with a IR laser mounted to the weapon. This is only good out to 200 yds or so. Be sure to check the regs in your state before proceeding.