Get the cheapest stuff you can find. I have found 500g for under $10. Take it in your postworkout shake (immeditely post-workout), with half the usual amount of dextrose. About 1/2 an hour later, drink another shake with just protein and the other half of the dextrose. This is the best and cheapest way to pack the creatine into your muscles. This is because the creatine is absorbed more slowly than the sugar, and creating a second insulin spike once the creatine is at its peak of absorption will really shuttle it into your cells.
Some creatine formulations come with a kind of "time-release" sugar to time the insulin spike closer to when the creatine is hitting your blood. You will pay about 5X as much for this kind of stuff.
JC