At this point I'm pretty far down the DIY rabbit hole, but I still would not consider it expensive, and I am barely financially stable, let alone "well-off". Considering what a huge part of my life it represents, I think it's the most value-packed hobby I could ask for, and in my case it generates a little income as well, which helps enormously to offset costs and keeps me motivated. I'm not at the point where I'm vaping for free, but that's not really a goal. I look at the juice I sell as lunch money, not an investment recoop, but you know, all those lunches add up.
If I knew then what I know now, my start-up costs could have been less, but everyone starts out as a newb. There's a lot of free, good advice floating around these forums, but there's also a lot of differing opinions. Until you dive in it's hard to make sense of it all, because you lack a point of reference.
The biggest thing about DIY I think screws up newbies is they go into it expecting instant gratification. This is not like throwing money and ending up with a bottle of perfect juice. That's what the vape shop is for. Even if you just follow the most highly rated ELR recipes, there's still time, effort, and patience involved, and always the possibility you won't be satisfied with the results. So maybe, "Somewhat Delayed Gratification" is as close as you can get.
But if you're like me, you've made those highly rated ELR recipes and said "This is ok, but I could make it better." Now you need to know what the chemicals you're using are and how they work, which is not to say you need a degree in chemistry, but you'll need to research. For example, what the fuck is this shit called Ethyl Maltol? What does it do, how does it react, and why is knowing about it critical to my DIY success? Everything you need to know about it is available for free on the internet, but if you don't have that core interest driving you, you'll get bored and frustrated really quick. It's not Cooking: Strawberry + Ice Cream = Strawberry Ice Cream (actually, it equals Mustard Milk, but I digress

). It's more complicated. You will fuck stuff up, you will fail, you will experience moments of sheer frustration, you will get impatient waiting 30 days for juice to steep, but all of that is off-set by all those "Oh, Hell Yeah!" moments. If you're easily discouraged by that stuff, I'd advise against considering this higher level of DIY, but if you're down for lots of research, experimentation etc. I'd say Go For It.
My only concrete advice is aim for mixing by weight from the beginning. I really wish I'd done that. Screwing around with syringes and graduated cylinders got old really fast, and it's slow to boot (lots of Quick Draw Syringe-fighters who've never touched a scale in their lives will argue that point).
Ie: your DIYer friend...Tell him what you like, and ask if he's willing to make it for you.
I sell only to friends, and I don't just say "Here's what I've got, Bro, take it or leave it!", unless I'm giving it away as a gift. I know lots of vapers, but have yet to meet one (in real life) whose tastes correspond to mine. I have them tell me what they like, then (attempt to) make the juice they really want to vape. One of my friends loves Red Bull (TFA Energy Drink). Personally, I find the stuff to be Just Tolerable, but he goes through 30 mls a week. My own opinion is of little importance though. For me, it's even more fun to create stuff that other people love than to just mix for myself. I don't see it as making a profit (like I said, lunch money), I see it as providing a much needed service. That's I guess where the ultimate enjoyment of DIY culminates for me, seeing it exceed mere self-gratification. Like how a chef feels when people love his food. Makes it mean something.
I am quite talkative today...