Pro Ebiz via Amazon offers the Uniden Guardian G755 Surveillance System for $249.99 with free shipping. Outside of the below mention, that's the lowest total price we could find by $30. It features two outdoor night-vision cameras, 500-foot range, 7" LCD monitor, and plug-and-play compatibility with a PC.

A close price: Pricebreak Deals via eBay offers it for $250.90 with free shipping.