What supplement would be best for me? I do not want something that will harm my body nor do i want creatine. I think I should go with either whey or muscle milk. My routine consists of 3 workouts a week, 3 running sessions, and a day off. A couple questions:
Is drinking a shake on only the workout days enough?
What supplement is best and where can i find it cheap/what brand is good but cheap?

You should use the protien shake everyday you can. I would try to not miss days. The body adapts to the extra calories and utilizes them efficiently. Skipping days can trick your body and the extra cals and what not will be stored as fat.

Hey!

bodybuilding.com is a great sight for cheap protein. PM me for a 10% off coupon. To check out the highest quality proteins:

Bodybuilding.com - Michael Warren - Easy-To-Follow Whey Protein Price Chart - Which Whey Leads The Way?

Yes, consume whey protein everyday...you want to be consistent with your protein intake, this creates an anabolic effect (builds muscle, burn fat).

MuscleMilk is a great formula and taste really good. But for more bang for you buck, you are trying to get whey protein. Try Champion Pure Whey, Dymatize Elite, Optimum 100% Whey...etc

You can also checkout massnutrition.com

personally, the only one i would recommend is this :
Impact whey isolate - Protein powders | myprotein.co.uk
in the non flavored form.

Excellent quality, and purity. None of the high fructose /artificial flavor ****tails that most common protein powders are, just as pure as they come protein.

Blend some berries or your favorite fruit, mix in some powder and enjoy. Healthy as they come, excellent quality.

edit: haha, it sensored the "c0ck" in "c0cktails"