Whats my best choice of Dirt

Im going to grow in a Plastic Cup for a few weeks, and transplant into something larger, I need to know what a good size pot is, and a good medium for the plant to Grow and finish in

I use half gallons - and some J Arthur Bowyer compost...I've read about a couple of people on here cutting a 3L pepsi bottle in half, drilling some holes and using that with fairly decent results

Depends on how big/long you plan on growing. Go to a nursery and buy the black pots for 0.75 a piece! I think the rule of thumb is 1 gallon for every month.

I use Fox Farms Ocean Forest with a small mix of Light Warrior and always get good results. I wouldnt recommend Miracle Grow, all the grows Ive seen with it end up with nute burn.