There is an active CryptoWall support topic, which contains discussion and the experiences of IT consultants, end users, and companies who have been affected by CryptoWall. In October 2014, the malware developers released a new version of CryptoWall called CryptoWall 2.0. This new version included some additional changes that are described in the next section. The ransom cost starts at $500 USD and after 7 days goes up to $1,000. This ransom must be paid in Bitcoins and sent to a Bitcoin address that changes per infected user.
Source: https://www.bleepingcomputer.com/virus-removal/cryptowall-ransomware-information