2006 Scion xA Dead battery off of lot. Is this normal?

I recently purchased a 06 Scion xA. The battery had to be jumped two separate times the day it was purchased due to not being run recently while sitting on the lot and not driven for some time. I understand that the battery needs to "charge" for a good while and it was suggested to drive it for at least a half hour. I have done so but when I went down to start my car this evening it would not start. Is this normal to take so long to charge? Or do I have a different problem (perhaps alternator) on my hands?