For quality you have two options. - Standard NTSC image (4CIF or Full D1) which is roughly 640x480 (not exactly). This is what analog cameras product and will connect to your recording unit (DVR) using either RCA (The yellow plug in the old white/red/yellow AV cables). or BNC (the old 10Base2 network connector with lugs). The cable can either be RG59 or Cat5+ with baluns. This is what most CCTV was for ever. The quality is not great, but can be compensated for by aiming the camera at where the action is going to be. If you want to read a license plate the plate must take up at least a quarter of the width of the screen to get a comfortable read (from a resolution perspective - lighting is another can of worms). A person's face for a "wanted poster" needs to be about the same size. The cameras run from $25 for the cheapest nasty crap you will ever see, for several hundred for brand name cameras with active IR filter DayNight and wide dynamic range (better handles variable light conditions) - Megapixel IP. IP just means digital data stream being transferred across a network cable (cat5e, cat 6 etc) rather than an analog image. You need the digital data stream for megapixel. Megapixels are rated just like regular cameras. Cameras used to start in the $1k+ range but the prices are dropping. Framerates are lower, generally, because the data stored would be much higher.