Hypothetical Casino running/risk of ruin equation question.

[ohgeetee]

Lets say I were running a casino game where on a computer, i pressed a button that gave a random number from 100-1000, and the sucker pressed a button that gave a random number between 1-1000, and if his roll beat mine, I paid him 1:1 and if I won i kept his bet. I have $100k in funds to run this casino, and more than enough suckers to play the game.

What should my range of allowed bets be to avoid risk of ruin, and what is the equation to come up with this?

please assume there is no trickery, all numbers are whole and perfectly random, etc. Its a clean game except for the exceptional odds in favor of the casino.