A 60ml bottle of commercial juice easily costs $15-20.
I buy my nic, PG, and VG from Liquid Barn and my flavors from a variety of sources (though mostly through Nicotine River). My materials cost for 60ml of homemade juice is only around $1.53 per bottle (not including the bottle itself, which you can recycle from commercial juice, or you can buy some, which only costs like $1/bottle). That's one hell of a cost savings!
That's made up of approx $0.33 of nicotine base, $0.09 of PG, $0.33 of VG, and $0.78 of flavoring. I buy PG/VG in 1000ml bottles and flavors I use a lot of in 2oz bottles, so I'm saving a bit by buying in bulk, but it still should only cost around $35 for the ingredients to get started in DIY ejuice - the cost of around 2 bottles of commercial juice. Grab yourself 500ml each of PG/VG, 125ml of nic base, and a handful of flavors and you have enough materials for at least 10 60ml bottles of ejuice (and you'll probably have PG, nic, and flavor leftover, the VG is by far the most used ingredient).
Also since moving to Germany regulations force u to mix the flavour yourself, so the labour for flavour is greater.