I am planning to buy a canon Rebel T3i, the additional cost for including the 18-55mm kit lens is only around $50. But since I am on a tight budget, I was thinking about getting a 50mm f/1.8 instead, and it is faster too. I would get a tamron 70-300mm also separately.

Since I am totally new to the scene, I'd like to know what are the possible difficulties of not having the 18-55mm. I don't plan to do a lot of landscape photos. For occasional casual group photos etc.(which could not be avaoided, since this is going to be my only camera) with the 50mm lens, I think taking a few steps away from the subject could be sufficient? Or could it be a bigger handicap than I am imagining now?