It’s always tough to say when it comes to used bottles of paint. They can be bought new for around £10 per bottle. So figure out what you’re happy paying and go with that.
I think you did the right thing leaving that. It’s not a bad price, but there were a lot that had been mostly used and you never know how they were stored. You’ll soon build up a collection of colours. I know I keep having to buy a bigger box to keep my paint it .