The real difference is that in most states these Pharmacy Technician certificate/degree programs are not required for national certification. It may be required in some states to attend a program, but I strongly suggest that you make sure it is required where you live. Otherwise, these programs can be costly and can consume as much time as could be counted toward an "actual" degree.
I recommend that you reply with your state, or check into the requirements there, more importantly. It should not be hard. You should be able to research this information online.
However, if you are interested in taking the course for your own benefit, I would enroll in a program such as continuing education would offer. Choose the program that takes less time to complete, as the fundamentals for a pharmacy technician can actually be self-studied, anyway. Some people may do well with that hands-on learning as opposed to self-study.
Anyway, there are a lot of books to study for the exam and you might want to start there by researching online- search the forums on that topic, especially since we have a few different threads with book recommendations.