I've thought about DIY but haven't gotten into it yet.  I do have PG, VG and some flavoring, but no nic.  I can see how you can save money diy-ing if you discount your time.  Of course with stuff like this, our time doesn't account for much in our minds.  I work leather and the time it takes to make a knife case well exceeds the $60 it would cost to buy one on-line.  But being the way I am, I proceeded to get into leather and spent $1000 on tools and materials to learn how to make my $60 case!  So typical!
Still, the best savings I've ever seen was on roll your own analogs.   When they went to $5 a pack, I was paying $1.20, and the smokes were better.  When they kept increasing in price, I still paid $1.20!
I think I'll get into DIY just for the fun of it, and if I save money (discounting my time)... Whooopiiiieee!