Price of a player declines but most of the times the players that are on the auction market are a steal for some of the people at the end of the season..For eg,I'm on Level 9 atm and I see a lot of 3 * players who are bought by level 7 players for just a token or so...
You would be up against Level 1,2 and 3 if the player is a 3 * player....If it's a 4* player then you're up against Level 2,3 and 4...If it's a 5 * player then you're up against Level 3,4 and 5...