You should be pleased that vaping on an electronic cigarette is cheaper than smoking traditional tobacco cigarettes. Once the initial purchase has been made, and you have your starter kit and 2 bottles of e-liquid, you should expect it to cost anywhere from $30-$70 per month. Expect to replace 2 atomizers per month and use about 60ml of e-Liquid. Your results may vary, but this is based on the average 1 pack a day smoker.
Atomizers are consumable products that need to be replaced monthly. Some users may get lucky and have the atomizer last more than 2 weeks, but the average lifespan is approximately two weeks.
The average 1 pack per day smoker will consume 30ml of >e-Liquid every 2 weeks.
In many parts of the country, a pack of cigarettes costs $8-$10. Assuming each pack costs $10, that is $300 per month. Compare that to $40-$70 per month and you should be very pleased.