Yes, by mixing your own and realizing what the ingredients actually cost, you'll find it difficult to justify the high price of premium e.liquid. It couldn't be easier: there are only 3 ingredients, plus flavor. You may also find that premium e.juice is excessively strongly flavored and come to appreciate a more subtle approach.
My recipe for a 200mL batch of 4mg 70/30 subohm e.liquid is: 8mL nic + 52mL PG + 140mL VG + 7.5mL flavor
Example from where I live (Canada):
250mL 100mg nic = $50 (20¢/mL) 31 batches
1L PG = $15 (1.5¢/mL) 19 batches
4L VG = $33 (0.83¢/mL) 28 batches
This is a year's supply of base ingredients for $98.
And then we have flavors which are the most expensive ingredient, costing $5 for each 15mL bottle (33¢/mL).
That means a 30mL bottle of homemade juice contains 24¢ nic, 12¢ PG, 17¢ VG, and 37¢ flavor; a total of 90¢.
So I can make my own for 10-20 times less than the cost of premium e.liquid and I'll never go back*.
Pro tip: you can buy USP-grade vegetable glycerine by the gallon from a local soap making supply shop where it is sold as an emollient.
*Except on my juice-sipping Vladdin pod system. A bottle will last for a month easily.