1. 35k will get you E. Anything less than that isn't a guarantee no matter how much others have said they've gotten it. Basically you're taking your chances!
2. There isn't a "normal" amount to pay but you want your cpm to be as low as possible. The "normal" amount is what you're willing to spend and I would venture 5 cpm or lower is a great deal for a MR. Any more and you're likely just paying too much. As said, "paying too much" is subjective.