Long story short: Because of some recent exposure (my 8 year olds birthday pressie) to remote control helichopters and a UAV conversation with a knowledgable neighbour I started to look at what was out there. Scary.
For under a grand you have something that flies at speed accurately to within a couple of inches, can be pre-programmed, has built in GPS, proximity detection and ground hugging sonar. Don't believe me, watch the vid and note how it flies between branches at speed - my personal fave is when it flies in one car window and out of the other.
These are arguably cheap, but as soon as a defence contracts, civil servants and free lunches become involved the cost sky rockets.
At the end of the day, these are just radio controlled planes with a camera, a GPS on board and transmitter (maybe some other bits and bobs). The technology has been round for decades and should be available easily for under a grand and it is surprising that it has taken this long to start getting these things out there in bulk.
Click, the BBC News 24 techno geek program, covered a mini UK drone this weekend - I think it's an observation platform rather than having an offensive capability but IIRC the sum of £22,000 was mentioned.
Quick warning, before you get to watch the spy bot piece you have to sit through an item about pixelated IRR cladding for armour.
My conversation with my neighbour was interesting, he flies a 10 foot span B-29 bomber and is well respected in the RC community. He has advised US plod a couple of times on the possibilities of civvy owned RC aircraft. I will not say which City he advised in but according to him the criminal use of RC aircraft is a threat taken seriously. Just waiting for the licensing police to catch on and control sales of the stuff.