Voltage per cell is depending on application, basically most Li-ion operate in the Voltage range 4.2V down to 3V. For light load application, the manufacturer will label it as 3.7V per cell, for heavier load application, manufacturer will label it as 3.6V per cell, because the chemical response is not fast enough and generated heat, according to the law of conservation of energy, power lose as heat will result in less potential generated.

That mean it have 4 cells inside.

2200mAH is RM25 per pieces
2400mAH is RM30 per pieces
2600mAH is RM40 per pieces

All brand new manufactured last year third to fourth quarter.