Hello Indonesia! Welcome Ghostclan.
I found that the first year of vaping, okay the first couple of years, were very expensive for me because I wanted to try everything, all of the flavors, and especially the varieties of clearomizers. Then glassomizers started coming out. And more flavors. Then better coils.
Then all of the continuous scares of vape bans, the hoarding, the worry worry worry, about having to go back to cigarettes some day.
Now I have my basics, and the equipment seems to last a long time, except for the coils that have to be changed now and then. I have one preferred flavor, one pg/vg ratio, a hoarded supply, and back-up everything. I feel that vaping would now cost less than cigarettes did/would, but the lower cost would be if I didn't have to continuously worry about bans, so I still increase the hoard from time to time.
Now I have read a recent thread that I interpreted as saying that 18650 batteries are disappearing from the market. Gawd. If that's true, then my huge supply of single 18650 plastic Bolt mods, which I don't use and only hoard, will be useless. I do have a few 18650 in plastic cases in the freezer, but no idea how long they'll last in use, or if I need to start getting 50 of them. Or 100, or what.
So if I look at it as a hobby, well, it's cheaper than collecting old diamonds or restoring vintage cars, or even a shoe obsession. We all started with some kind of addictive element in our personalities, so maybe vaping is the cheapest and safest answer to that.