My quest is to get the final item. Im at 310,000,000,000. wish me luck boys.
It is very unlikely that it is even possible (not coded in to the game).
1) The behaviour of the numbers at certain points (becoming negative or zero) would indicate that "signed int" types are being used in the code, which cannot represent the cost given. Even a 64-bit int can only hold a number up to 9,223,372,036,854,775,808 (signed) or 18,446,744,073,709,551,616 (unsigned).
2) A "float/double/etc" type with 128-bits might be doable, but the observed behaviour of the game does no seem to indicate that the developers used floating point types large enough for the cost shown.
3) While there are arbitrary large number libraries/packages, again the indicators suggest no such library is in use.
4) I count twenty-nine 9 digits, which even if you were generating 310,000,000,000 per second, would take 10,228,965,156 years to complete--that is 10 billion years. I'll check back with you around that time... 8-D