Where can I buy (UK) animated video backgrounds?
and how much should I expect to pay?

thanks

A

scope out artbeats.com and digitaljuice.com

Because they are used so much, you'll wanna doctor em up a bit.
Using them as is screams library cookie-cutter from the back of the room.
You may also wanna do a quick search and snag some of the freebies that can be found.