It really isn't necessary to spend hundreds of dollars on equipment. I once bought a Nemesis clone from Fasttech for 9 dollars. I still have it, and it vapes like a dream. I now have a number of moderate-to-high-dollar authentic mechanicals, acquired over the years. I bought most of them here on the classies, used, and waited until I got a good deal. The authentics are generally better. The use better materials and the quality of work is superior. This makes them easier to use, and safer to push them closer to the ragged edge of possible. The thing is, an extra 10 seconds spent replacing the battery because the threads are not as polished as on a mod costing hundreds of dollars more is not really a big deal, and I don't push the gear to the ragged edge of possible anyway. And once you get the mod assembled with the battery inside and the topper screwed on and filled with juice, they don't vape a lot better. Again, unless you are using the gear to it's maximum limits, the additional .00001 volts of voltage drop you'll find between 302 and 316 stainless is pretty meaningless in practical terms. A lot of what you're paying for is the name, and the cachet. Feel free to do so, if you like. I do, but mostly because I love them as works of mechanical art. But you don't have to. As to regulateds, again, you don't have to buy top of the line, unless you just want to. Sigelei makes their Mini Book, a 40 watt, TC, Single 18650 mod, and I just bought one as a Christmas gift for $34.00. You can buy the Sigelei 150 watt mod with TC for 90 bucks and without TC for 65. And Sigelei is a well known and respected company with a reputation for quality build and long life equipment. The parts that go into a Hexohm v2.1 cost less than 20 bucks, but Vapecrawler only shows one priced under $180.00. I paid well over a Franklin for my Snow Wolf 200W TC machine. Does it do anything the Sigelei 150 won't do? Considering a) I wouldn't even dream of vaping anywhere near 150 Watts, never mind above; and b), they're made in the same factory, no, it really doesn't. I bought the SW because the Siggie 150 wasn't yet released and I didn't want to wait, but I wouldn't make the same choice today now they have been. Is there a quality difference? Yeppers, that there is. An iStick is not an Innokin is not a Sigelei. But you know what? Given identical toppers, they all vape.
Much the same can be said for toppers: You can pay top dollar if you want to, but good gear is available much cheaper. I rebuild, so I don't know much about replaceable coil tanks, but I use A Fogger V6 for dual coils and a Lemo2 for solos, and both can be had authentic under 30 bucks. I just bought an Indulgence Mutation MT tank-- it's not here yet-- because of the gigantic air flow and the huge juice channels. If it vapes like people tell me, it will probably become my favorite dualie tank. I bought it under 30 bucks too. I don't really need a Squape for over a hundred. I have an authentic Council of Vapor Aris Pro dripper, and a Wotofo Sapor; I'm hard pressed to tell you which I like better for flavor. They were 26 and 19 dollars respectively. And, while I get great pleasure from using them, and do so by preference, they don't vape a lot better than the two Plume Veil clones I have, both less than 10 bucks. Would I like to have an authentic Plume Veil? Definitely. Paying $125 for one is less attractive. I've vaped an authentic Kennedy Competition dripper, and it is a cloud machine for real. I'd love one, but they're a hundred bucks used. And I get about as much cloud from my authentic ($15) Fishbone v1, and from my ($10) clone Dark Horse.
So you make the call. If it's worth the money to you, by all means. But if not, you don't really need it.