Oops, I forgot one thing.
It exits as soon as it's done, so this will make it stay open, although be it's pretty crude, so be warned.
# Hi forums!
a = raw_input("Gold or XP?")
if a == "xp":
b = input("How much xp until next level?")
c = input("How much xp do you have?")
d = input("1000, 2000, 3000, 4000, or 5000 per round?")
e = ((b - c) / d)
f = input (e)
if a == "gold":
b = input("How much does it cost?")
c = input("How much do you have?")
d = input("50 per round, 100 per round, 150 per round, 200 per round, or 250 per round?")
e = ((b - c) / d)
f = input (e)
EDIT: Forgot some stuff