A quid is a slang term for the British pound. So currently, 1000 quid (or 1000 pounds) is about $1500 US dollars.
Sidebar is a theme feature introduced with Version 2.2. It's basically a vertical column provided by a theme for displaying information other than the main content of the web page. Themes usually provide at least one sidebar at the left or right of the content.
An example of a sidebar is when a judge wants to have a prosecutor step over to the side of the courtroom and explain the relevance of a piece of evidence. YourDictionary definition and usage example. sidebar.