You're in Pakistan, perhaps looking
here might offer you a better resource base as the site linked seems geared toward vaping in Pakistan. Please understand, I'm not sending you away from here at this site. No, not all. I happily welcome new vapers aboard here.
As
@pulsevape points out we all get a start by talking with other vapers and feel keen to help new vapers as a means of gratitude.
So please do feel welcome here, you might though also look at the other site, simply because it discusses everything in relation to Pakistan. Ejuice has three main ingredients if you use nicotine.
1. Propolyne Glycol = PG
2. Vegetable Glycerine = VG
3. Nicotine = N
Aside from this it also might contain numerous flavoring oils or extracts. You might only need one or two flavorings though it depends upon your taste and what flavors you desire. I can vape an unflavored
base ejuice that is 80% VG and roughly 20% PG and N. I vape 18 mg N per 1 ml of juice. If I mix this up in a 10 ml bottle the math for figuring out the reciepe is easy enough.
A Simple Base Ejuice
8 ml of VG
0.20 ml of PG
1.8 ml of N (This might be in a PG
carrier solution. If it is not in PG, it will be in VG. Adjust accordingly.)
The above has no flavor except what little subtle sweetness might be in the VG. I can and do vape this often. I also use it to dilute down other juices which are already mixed and flavored. This makes juices last longer for me. I also then can somewhat combine various flavors and get an idea of what flavorings I might want to buy for mixing my own DIY juices. I do this for a little while, vaping at times what is called
junk juice. For me this junk juice is somewhat valued, it is learning aid.
Tovicology is a minor concern. Let me phrase this catiously, it is a minor concern in that if you spill juice on your hands you go wash your hands off before eating or preparing food eaten or given to pets. As consumers we are not given access to typically seriously concerning nicotine toxins. Granted, yes, you can buy nearly pure nicotine which is a serious concern requiring proper chemical gear to handle. It is unlikely you will unknowingly make such a purchase without due precautions and knowledge. You can though buy nicotine that is relatively safe for use in making ejuice. You still need to handle it cautiously, washing your hands after mixing.
I understand you are busy and will likely continue buying already mixed juice. Thought I would offer you a glimpse into juice making, I'm not an expert on it but do dabble a little for myself only. The reason I show you this glimpse is to show you another possibility, which might save you some money, if you so choose. There's plenty of juice making experts here and possibly on the Pakistani site I linked to above. Folks often don't mind sharing reciepes, tips, tricks in doing juice mixing. Something to consider, possibly.
Please excuse me, off to bed now as I see my time here is 4, nearly 5 AM. I am in EST zone.