NVIDIA GTX 1070
The NVIDIA GTX 1070 is not only known for its gaming performance. Its 30Mh / s hashrate is reached without asking too much energy. Remember that power consumption is a very important factor in making your rig profitable. Like most recent graphics cards, the 1070 costs a few cents, but it is a card of very good quality of manufacture and has an interesting life time.
Average price: 450 €