hello Jen, welcome to the forum. I'll be around if you need any help. Private message me if you want.
If you smoked 15 cigarettes a day then you'll do well with 12 to 18mg juice. A lot of us start with 24mg juice and step down to 12. In my personal opinion, 18 and 24mg juice is way too high. Especially if you like longer drags. In my opinion, the amount of cigarettes you smoked each day has NO correlation to your juice's nicotine level. lol. Thats just my opinion. Your juice's nicotine level more-so correlates to how long a drag you take, how many drags you want to take before you put your PV down, Throat Hit, etc etc...
If your vaping like you smoked, and it seems harsh, or it seemed like you were feeling a buzz before too quickly or too easily, and you want to continue vaping in the way that you are, then you'll want to lower the nicotine amount. Although you will find that the first day or two of vaping, it will be a bit harsh on your throat no matter what MG juice your using. The nicotine in the juice hits your throat differently compared to cigarette smoke, and your throat will need to get used to it. But do not fear, it WILL.
I personally vape 12mg juice. This forum is full of people that swear by 18, 24, even 36mg juice. GROSS! YUCK! lol. If I picked up 18mg juice and tried to vape it like I vape now, I'd get sick within 4-5 puffs. And idk about you but my cigarettes lasted longer than 3-4 puffs. So, if you want to shorten the amount of puffs you take, stick with the 18mg juice... if you want to vape like you smoked, at least for the first few months, then you'll want lower MG juices.
As was said above, Walmart has pure Vegetable Glycerine. Just ask a pharmacy technician to find it for you. If they cannot find it for you, just ask to speak with a manager and they will be able to locate where it is in the store via a registry computer. You can then use the pure flavorless vegetable glycerine to lower the nicotine in your juices. Unfortunately it will also reduce the flavor. Which may or may not be good, lol, depending on how you like those flavors.
As for new juices, there are a ton of GRRREAT vendors that advertize here on this forum. You can find them by going down the forum to look for the vendor's forums.

Again, if you have ANY more questions, feel free to shoot me a message by clicking my user name and selecting "PRIVATE MESSAGE" from the menu.
Enjoy your journey
