Auction vs Scouts....
Hmmm.... I'm a scout buyer normally, mainly because I like a high quality side and normally get to work with a lot of tokens from videos in the past historically, Theres been seasons where I have earned 400 tokens which means in turn I can buy quite a lot of scouts, Until recently, I had a squad rota and normally would replace my 4 worst players which would be around 4* with 4 youngish scouts 22-24 years old with ratings that end in 4 or 9 if I can. A scout player on the younger 22-24 and qualitys that end in 4 or 9, would get at least 4 seasons at my club, when you do the maths, it works out at 12.5T per season, which isn't bad when you buy 5* for auctions for around that cost and they would of got 1-2 seasons before being replaced by better players, which in turn given the starting quality of scouts it makes them slightly better value than buying 5* players from the market and it knocks out the uncertainty of getting involved in an unwanted bidding war which could drain your tokens and money.
As for negotations, well most bids would get rejected from managers since they are most likely to be players that managers don't want to sell and if you do get a bid accepted, you probably could buy a scout player for just a dozen more tokens or so.