The mod use (Joyetech Ultex T80):
Ultex T80 (Ali)
The RBA I use (Wotofo Profile Unity RTA):
Wotofo Profile Unity RTA (FT)
Extra mesh coils here:
Authentic OFRF nexMESH Coil Rebuildable Mesh Sheet (FT)
Extra cotton made especially for the Profile Unity:
Cotton (Ali)
The cotton can be bit harder to install. Just don't follow the Wotofo method. Some searching will turn up the "shoulder pad" cut which leaves a bit more around the top than at the bottom. But it's also pretty hard to get it wrong after watching some Youtube videos. Screwing it up will leave it a bit leaky. Carry a bit of tissue in your pocket...
Sorry about the mixed sources. Fasttech can be great for getting super discounts (use MAP as a coupon on a lot of things to get the sometimes deeply discounted unlisted price). Ali tends to be factory-direct so also cheaper (and I don't know Fasttech can undercut the manufacturers and still be genuine, but seriously, it is).
As for drip tips...
A,
B, C - standard 810s should fit but... sometimes they don't. I guarantee these all do.
Mini fill bottles in case it's helpful:
PE Empty Needle Refiller Bottle (FT)
And finally, the best for last:
Batteries - these are high-drain batteries. For some reason, Korean stores will overcharge like $10 for a 20A battery that can't even go past 30W. So you'll need a 30A battery (higher A usually means lower mAh) like these. VBatty has genuine LG and Samsung batteries waaay cheaper than I've seen in Korea. The shipping hurts but not as bad as the waiting. It can take 6 weeks or so. If you have time, search for Mooch on Facebook and his blog. He tests hundreds of batteries for safety and power.