I paid $400 for a Mint- Canon 7 with a 50mm F1.4 lens. The Selenium cell works and is accurate. That was last year right after Christmas and before Taxes, a good time for EBay buyers. I paid more for my first Canon 7, it had been CLA'd and is my main user. It's light meter is perfect, either kept in a case or a new Cell.
I think a good user Canon 7 with a working meter should go for $200.
A CLA/standard repair is $130 at Essex, if you get a non-working unit cheap. Meter repair, if possible, would be more.