A good article with advice on feeding budgies-
http://www.budgieplace.com/advanced.html

I used to keep budgies. I always kept more than one, as they like to socialize. After they were "tamed", I let them fly in a closed room. They would eventually return to the cage if it has their food and toys.
I never really got into advanced taming since I was away working most of the day.
The place I linked also has a good basic care section.