Put some money in the bank (about half of what you have) and try again.Money on your character is saved as a 32-bit signed integer value. Maximum possible value is 2,147,483,647.You are very close to the maximum, and if you add any more, because of the way integers work, it rolls over to its minimum value of -2,147,483,648, which is just a bit short for any purchase you'd like to make.