It is a good idea to stick with the same primer. changing a primer can spoil a good load. So consider what your sources tend to have in stock.
If you load ball powder from time to time, the Winchester Large Rifle primer is a good choice because it is made a little hotter for igniting the Winchester ball powders.
Primers come in cases of 5,000. It is prudent to buy a few cases to start with and then buy more when you open the last case. That way, if the same brand primer is not available, you have some time to look for it.