When I use to buy locally, my favorite shop sells (after tax) 30ml for $11, 60ml for $20, and their premium brands (like Mad Alchemist, Suicide Bunny, etc.) generally run $22-30 for a 30ml bottle. I use to buy 240ml at a time, every four or five weeks, and would spend $64-80 every trip in the door, depending on coupons, sales, or earned loyalty points . I made a recent trip into the shop to pick-up a door-prize, and I checked out their juice prices... they've not changed since I started vaping, but at least they offer 120ml bottles now for $35 (house brand, single-flavor stuff, but only in 80/20 PG/VG).
When I bought online, my costs would range from $7-15 per 30ml, without bulk discounts or coupons. Shipping is the real drag for online juice purchases... you have to buy ~ 240ml minimum to really break-even for prices. Many of the "basic" juices I would buy online, after shipping was added in, it was just as cheap (or cheaper) to buy it locally.... unless of course I was buying a couple dozen bottles or had a coupon code
Which is why I started DIY... for the cost of two months worth of juices locally, I can buy supplies to make 6-10 months of what I want.
Now, I DIY, and mix what I like, how I like, when I want... and have saved hundreds of dollars (probably more than $1500) over the past couple of years!