I don't think I'm saving all that much to be honest. I switched to making my own liquids as paying £10 for 30ml of liquid which lasted me 2 days was quite sore, probably more so because I bought in bulk so the initial outlay was more noticeable than the cost of a pack of cigarettes every day. But of course getting into making own liquids in itself is highly addictive and curiosity takes over and before you know it you're coming down with different flavour concentrates. Then different flavours require their own dedicated tank and each tank requires dedicated mod and batteries (maybe this is just me). Then there's that initial outlay for mixing stuff...bottles, syringes, VG, PG, nicotine, concentrates etc. I think my first order of stuff was somewhere around £50.
I've just roughly worked out what I've spent so far on material to make my own coils. Bit of an eye watering £140. This includes the 5 RTA decks I've bought compatible with 3 of my tanks (wtf!) wire, toolkit set, ohm reader & battery, ceramic tweezers, pre-made coils, cotton etc. I'm not too fussed though because it entertains me and keeps me occupied.