The cheap price for a player is of course also influenced by the quality and way he played in the old team, so no one can deny this. Because usually when a player has very good quality and is reluctant to be let go by his old team, of course the offers that come from other teams who want to buy him can also be bigger as long as he is still healthy enough and still young enough in terms of age.
The quality and price of a player has got a whole lot to do with his performance so far at a team through the season or for as long as he has stayed in the team so it's usual that these players are rated and priced by their performance so far which could entails possible good potential in such players.
The number of goals scored I'm a number nof matches followed by assist he's made so far and speed all these co tributes to the price of such players. Sometimes their present team do offer to increase their wage and pay them them much higher than others may want to offer there by making them priceless and not affordable to other teams who are trying to come bid for them and in some cases these teams further raise their price especially if their is a position they feel crucial for such player to come occupy .