"As always, you may wish to proceed differently, and YMMV..."
Made my first DIY batch today. I bought 36mg PG nic juice, VG, peppermint and cherry flavoring, and some 10ml syringes. Put 5ml nic and 10ml VG in a 30ml bottle. I then added 10 drops of each flavoring and tasted, and repeated 3 times. I'm guessing approx 1 ml each. Results exceeded expectations. Roughly 66% VG, 11mg nic, shake and vape, best juice I ever had. Roughly $30 for about 400ml of juice. $6 per 10ml bottle at my local B&M, vs $0.75 per 10ml?
OK, I'm going to get some PG and some better measuring gear, and recipes with more flavorings will up the price some, but I still don't see the cost going over $1/10ml, and this is buying in the smallest lots for a test run.