do you mining for invest? or mining for learning bitcoin? or maybe you mining just to get profit?
if you mining for invest, then i recomended for it better you buy bitcoin right now and invest it for 5year.
if you want to learning just buy 1 card, try it yourself by diffirent algorithm
and if you want to get profit, is not easy as you think, calculate your electric cost, calculate your maintenance cost and of course you must try diff algorithm to get "perfect profit" like mining when new coin release and hodl it.