There are several amounts that may show under your account balance:
Cash Balance
These are your unrestricted funds, which you can play or withdraw as you like.
Sports Bonus Balance & Casino Bonus Balance
These contain bonus money that must be wagered on either Sports or Casino. Once you have fulfilled the wagering requirements, this money will be converted to cash. You can check your active bonus section for more information.
Casino Buy-In Balance
The qualifying deposit amount for a casino bonus will be credited to this balance. These funds will be restricted (ring-fenced) to Casino. However, these are real funds and can be withdrawn (including any winnings).
Free Spins
Winnings from free spins are wager-free and credited directly to your Cash Balance.