Scout players are worth the weight in gold and in my opinion every team should have at two or three to help balance the team and give you a little extra but now is not the time to buy 50T scouts!, wait till the first day or two of the season so you get a full season from them or risk them losing a star if you get promoted.
The main thing to be aware of is that dont expect them to come blazing out the blocks as some take a season to settle then come good the next, others play great this season and average the next, I have found they go in seasons ..good- average-good etc, you should treat them as an investment and play them to there strenghts!.
I always have 5 or 6 minimum to cover two teams(22 man squad) you can look to get young players on the normal market but expect to in bidding wars for real quality 5* players.