Very cheap for you enthusiasts maybe. For non-enthusiasts a cheap card is 50 bucks. Midrange 80, High-end 100, 120 if we want to go overkill. Not to mention always the same thing: if it's for mining, it's trashing money. If for learning, better to upgrade the whole system.
you can find it for 50 buck even new lol
750ti is very cheap
Max i can spend is 400$ maybe $1000 budget
well buy a gtx 970 then, but keep in mind that everything is not profitable right now