Actually Dish got a lower interest rate than originally expected and expanded the debt offering to $750 million from the orignal note offering of $500 million.
To put this in perspective it is about 3-5 satellites worth of money (including launch costs).
Over Dish's existance they have routinely borrowed billions, and have repaid billions. Dish (like other providers including DIRECTV and Cable) has large cash flow. They get a ton of money each month from subs, letting them repay loans over time.
At the end of last quarter Dish was sitting on about $1 billion in cash and Echostar was sitting on about 650 million.