I buy cameras from hk sometimes. They are called a7 on ebay. Come with 30 IR leds and have audio. They sell for around $20-$25 shipped. They come with with different lenses all time is the only catch. So far the only problem I have ever really had with them is polarity. One time hooked up backwards and they'll catch on fire. LOl
Great for cheap general use. Only way you'll really ever identify some one is if you have a shot within 10' - 15' max. But sometimes that's all you need. They are so cheap though you can put one above every door and window on your house for under $200.