Sorry if i'm not being very clear, I
buy 4x10ml every 2 weeks this costs me £8 total, could I make it myself cheaper or am I cheaper to keep buying from
shop
That's not a bad price.
Yes, you could make your own cheaper, BUT:
There are some startup costs getting supplies
There will be some wastage - juice you make that doesn't turn out right.
There will be some extra effort involved.
If your local shop has juice that you like at that price, then doing DIY probably doesn't need to be a major concern.
(Forgive me for working in dollars here, but I'm not sure what 1/100th of a pound sterling is. Is that a pence? Also, I don't have that "curly-L" on my keyboard!)
If you were paying $8 for 40 ml, that's 20 cents per ml.
If you did DIY, you might be able to get that down to 5 cents per ml, perhaps a bit lower. But probably not a lot lower.
And if you did invest in supplies, you would soon find that the flavorings are the biggest cost.
I can buy a liter of 100mg/ml nic for about $50. If I'm making a 10ml bottle, at 10mg strength, it costs me 5 cents for the nic.
I can buy a gallon of PG and/or VG for about $25. 10ml of that would cost about 6 cents.
So, I could make a 10 ml bottle of
unflavored 10mg/ml for about 11 cents (assuming I invested about $75 up-front). Plus the cost of the bottle! Or a little over a penny per ml.
A one-ounce bottle of flavoring might cost $5. That's about 16 cents per ml. If I mix this flavor at 20% that will cost about 3 cents per ml of e-juice.
So, there's an example where if you invest up front, you can make e-liquid for about 4.1 cents/ml. As opposed to 20 cents.
But, if you buy smaller quantities of stuff, you might pay more. In the UK you might pay more (particularly if you order it from the US). $5 for an ounce of flavoring is pretty cheap, they can certainly cost more than that. (The price I picked was from The Flavor Apprentice).
Hope I did all the math right, but the bottom line is that the juice you're currently buying is certainly competitive with DIY, and a lot less hassle! (A dollar is still worth almost a pound, right?)