I'ld like to give a tip for the managers who still don't know about the free driver market.
Just go to search menu and type a driver name. For example "Alan Smith". There are lots of free drivers under the name of Alan Smith. This is only an example for you to find drivers with high talent. I mean very high talent such as 18-19-20. Try it.
And there is one more tip for you guys. Just go to your league's standings and search for the previous end season tables. There are so many drivers which are released from the teams somehow.
Hope these tips work for you.
Cheers.