I can get players down from 110k to 70 k sometimes.
It's all about adding bonuses and clauses. For example, add in a team of the year bonus, top scorer bonus, bonus after x amount of goals, minimum release clause, contract extension after x amount of games.
All the clauses don't really hurt me or my financial line (that striker was no way going to be the top goal scorer, nor was he going to score 30 goals in a season) because I'm very certain they won't be activated. yet these things can make the agent happy and I managed to get Welbeck from 110k to 70k just by adding in these clauses.
Also, if you see the agent has a high fee demand, often giving him a high agent fee can help A LOT. I've been able to get players from 100k to 50k and loyalty fee from about 3 M to 1 M simply by pumping up the agent fee. Talk about a ****** agent!