ejr3gan, it is quite obvious that you are pursuing an aggressive loss recoupment, such as Martingale, as people here have already suggested.
At some point there wouldn't be anough money offered for the current price to match your bet. But Rubold gave you a good piece of advice: to bet at "best price to match" instead of current price. In that case your bet would be split into several parts, each matched at a different price. You will wipe out all current back offers, and also this will result im much less profit than expected, but at least you will not go totally bankrupt. All that said, you must have enough money in your account to cover than liability.
To see how much money is in the market for a selection, click on its name to open the table showing you the amount offered at different prices.