After a long absence from the ECF, your post was the first I clicked on. First of all, welcome to your new lifestyle, you won't regret it.
I smoked for more than 45 years and my kids asked me to give vaping a try and they would cover the expense for the first few months. I agreed, and 2 weeks after I started vaping I realized one day I had not smoked my allotted daily cigarette for 2 days without even thinking I needed it. I sat down and cried tears of joy of finally being free!
Each person has a different experience. I haven't smoked in 6 years now and have not missed it at all. I didn't have to force myself to vape, there was no will power involved in my case (remember I had been smoking for a lifetime).
I was spending $66 a week for a carton of cigarettes. I would go through it in one week. Now, I don't spend more than $100 a month and sometimes even less or nothing at all if I have enough coils and ejuice left. I do make sure that I have plenty of those on hand. Get yourself a simple set up such as an ego battery kit and simple atomizers. Make sure you have two batteries, not necessarily 2 kits, as you will need to have one recharging at all times so you don't run out of battery use. I've found Discount Vapers to have excellent customer service and a good stock of quality gear. They have atomizers that go for $1.99 if you buy two. They take the Kanger coils for the Evods and a package runs about $8 for a 5 coil blister pack.
I personally buy my ejuice from Vape Wild and their prices are very reasonable. They also send you the order free of shipping if you spend more than $25 or 30, and will include a couple of 10 ml bottles of sample ejuice for you to pay forward or try out.
Your constant expense will come in keeping coils and the ejuice. Don't buy every "shiny thingy" you read about and you will be saving buckets full of money, trust me.
Once you've learned a few more things about dry hits, plastic tanks vs glass tanks, the difference between the different mah's, and more, then you'll be ready for an upgrade.
Start with a high nicotine content (I started with 18mg) but also get a lower bottle of ejuice in case it's too much. After 6 years I'm down to 1.5mg nicotine, and am not sure I'll go down to 0mg because of the research on dementia and alzheimers proving that it's beneficial to staving it. (I'm 68 years old now).
Good luck to you on your vaping journey and feel free to ask questions.