Although it's not typically the smartest thing to do to buy large volume of BTC through Dialcoin yet, it seems 65BTC instantly through Dialcoin would cost your phone bill £387 (about $600USD) based on your country and carrier selection. For your specific case that would be about 4x the price of bitcoins at normal exchange rate right now. Only use it if it's an emergency, but it's there just the same.
Presumably if bitcoin prices go a lot higher then dialcoin will become a more attractive option.
I know this isn't the thread for it.. but while it's come up, roughly what proportion of the difference is a fixed cost and what proportion is a percentage? Does it vary greatly by country/provider?