Many places sell nic juice in you choice of PG or VG base. If you want to make 100% PG or VG just order that as the base and purchase additional PG or VG. If you want to make a PG/VG mix then yes you'd have to purchase both. What ratio you intend to mix will determine how much of either you purchase. I started off with PG nicquid and bought 2 additional bottles of PG and one of VG because I'm trying for a 70/30 to 80/20 ratio. I'll use much more PG than VG. If you do the math on your target ratio you'll know about how much to buy of everything. Flavors are another matter. I'd suggest buying quite a few since you may end up not liking them even if they look good on paper. Besides, they're small bottles usually so you'll go through them quickly. I use a whole one dram bottle of Lorann's when mixing 30ml of juice in some flavors.