Everyone has had such great answers to a difficult question. I would like to add:
1. I definitely agree with the suggestion to start with a small project first. Especially if you are teaching yourself on your own. What I consider to be my first real quilt I took a class at my local shop. I think it cost me $150-$170 including fabric, some notions, batting for a lap quilt.
2. Your first quilt might end up being more than you would normally spend because you don't have a stash. I believe that as you quilt and your stash builds the cost per quilt goes down because you won't buy as much for each quilt. Unless you're doing something special, you buy a kit, etc.
Good luck and we all look forward to seeing some of your work!