If you're not bothered about whats on it, there are one or two collections of vinyl on ebay at the moment.

Why not ask on freecycle - there is quite often people wanting new homes for them.
As for car boots - you will have to get up very early for a bargain - quite a few of the regular stall holders do the rounds buying boxes full of them for next to nothing before selling at dearer price.

That can be a painful option - better of managing with what you've got