I am thinking of buying a 16mm indexable end mill (picture 1) to use in my SX3 milling machine, i know nothing about indexable end mills so have a question about the inserts...

They sell the inserts also (picture 2) but seem expensive per insert, my question is, can other brands of insert be used with this end mill? And if so how do i know what type to buy? As after looking on eBay there are many many different looking types.