I agree with Diche (as I think we did on another similar question), The FastTech clones of the GP Paps are superb, no problem, and dirt cheap. I'll give you a link as they have now taken the name 'GP Paps' off the listing because of legal issues.
$17.83 Brass + Stainless Steel Mechanical Mod (Full Set) - brass tube at FastTech - Worldwide Free Shipping
Next you need a dripper. I would recommend a dripper because as you say you can change flavours easily, and if your coils and wicks are... shall we say... below par, they will still work. If you use Genesis or Kayfun style tanks, there is a steeper learning curve -- if they aren't built right they don't wick well.
I haven't tried it yet because Chinese post is kinda slow and mine hasn't arrived yet, but I'll go out on a limb and recommend the Vertex:
$9.49 Vertex V2 Style RDA Rebuildable Dripping Atomizer - stainless steel + copper / 22mm diameter at FastTech - Worldwide Free Shipping
Personally, at the moment my favorite is the Veritas which I love. But some people say it is hard to build on. I never had any problems but it does have an unusal design, which is why I recommended the Vertex which is supposed to be better and has a conventional deck.
And no you don't have to vape sub-ohm. I love Genesis tanks which have the coil up high which gives a warm vape like a dripper. but they wick slow so you can't run them at low ohms, They work best between 0.9 and 1.3ohm. As I am used to that I generally run a dripper at the same kind of ohm, and that suits me fine.
You just need some batteries, cotton and kanthal.
Efest batteries are pretty good and sold through authorized resellers so you'll know you aren't getting fakes. You'll also need a charger. I seem to remember MyEpack has good prices.
As for kanthal wire, many places will stock A1 in various gages. I don't know why people on this site talk about millimeters... 28 guage will get you started.
And if you want to make coiling so easy a blind man could do it (pun intended, challenge offered), FastTech now stock these:-
$6.82 Kuro Koiler Wire Coiling Tool (3-Piece Set) - CW-20 + CW-25 + CW-30 at FastTech - Worldwide Free Shipping
You can test resistance on the devices you have, so that is about it except some tools, scissors etc.
If I can do it, anyone can do it. It isn't nearly as hard as you think, because you probably won't be trying to build insanely complex sub-ohm coils. Six wraps of 28awg kanthal and just add cotton.
Good luck!