Hey Sam. So from my experiences of using my good old visa is that the more players you buy in quick succession the more you will pay for each of them. So lets say your first was $5, then the second will cost you $10 if you buy immediately, the 3rd will be $20 and so on. However, after your 1st purchase of a $5 player the lowest you will buy them for is now $10. So, when you buy a $10 player, wait a few days and the price will drop again from the new price of $20 back down to $10. You can normally buy 2 or 3 players per season (including the off season too) using this sensible technique.
Hope that makes sense, if not please do ask.