EA just recently announced in a blog post

EA just recently announced in a blog post the introduction of price ranges in Fifa 15 Ultimate Team. At the time not much was explained as to why these changes are being made but it was obvious that it was due to Fifa 16 Coins  fair play.Now, EA has come forward with a detailed explanation.

According to EA, FUT should be fair and fun for all, so over the past few weeks they have made some adjustments. We have implemented a lot of changes to FUT in the past several weeks, including our decision to make the Transfer Market inaccessible via the Web and Companion App, and the introduction of Price Ranges within the Transfer Market.

EA wants to make life difficult for coin farmers and cheaters. Such people generate FUT coins illegitimately in the game via bots and phishing scams. As result, coins are flooded in the market and prices of  Buy Fifa 16 Coins high value players go way up.http://www.fifa16shop.com/