Everyone on this forum is so nice and patient, this topic has been covered so often. That said, there has been so many good points in this thread that I can't really expand on it much, but I'll try.
A tour will cost as much as you want it to cost maybe more. Truth.
You've already been ripped on for the packing list, and when I first read it one of my first thoughts was the clothing. 6 pairs of socks? Seriously? Take 2-3 pairs of good wool cycling/hiking socks. My strategy is usually to take one see of layers for off the bike for the temps I expect to encounter. On top of that I'll take two cycling shorts, two tops (one merino and one polyester jersey), and that is it. My long tights are in my set of layers for off the bike that double as bike tights. Similarly a lot of my off bike clothes can be layered up for on the bike if I need them. As someone pointed out wash one pari of shorts each night, andlet them dry out overnight and the next day while you wear the clean ones. Will they always dry out? No, but wearing the same shorts two days in a row won't kill you.
I've met guys eating very cheap food, begging for free bread at subway restaurants, and it wored for them, you can do that stuff when you are young. They sure did thank me when I gave them some tomato paste to mix in their dry pasta however. I mean come on, how much is a tin of tomato paste? $0.50? Problem with that is that you won't use the whole thing in one meal, and it's difficult to save. In the same vain I'd like to know how you will make sandwiches cheaply. you will buy the meat, which never comes in small enough packages, and it is difficult to store properly. That means waste. IMO if you really want to go cheap them you need a stove. Sure, you can get by without one, but for anything over two weeks give me a stove.
Anyway, you seem pretty convicted to do the things the way you want to do them, so do it. You'll learn along the way, and have a blast while doing it.
Broken record ---- do some short tours first! Learn what works and what doesn't