My wife did a summer bike tour with world famous a-frame tent, bike she picked up from a charity etc... She had a great time.

If you want some credible version of "real" touring stuff:

Bike 1300-2000, There is also the windsor tourist etc... or second hand
panniers, assuming 4 100-200.
racks assuming 2 50-200
tent 200
bag 100
foam pad 10-30
misc gear like post stoves, lights etc, 200 and up.
Clothes. I wear regular clothes, but made inserts for the seats, and use cycling sandals. so call it 100-200, gloves 20

There is really no upper limit, once you enter the custom everything,a nd bike jewelery, rancy camping worlds. You could spen 10-20K pretty quickly.

It is really hard to know what daily costs are. That is a regular thread item. I found it expensive because, while I am cheap, a bike trip takes about 10 times longer than an equivalent car trip, so that is 10 times everything, except gas. Some people say they can do it for 10 bucks, but there are also places where that is the cost of a cup of coffe. Like if you are on the road and had a red bull and a coffee, that's ten buck. I don't drink energy drinks or store coffee at home, but whatever you want on the road, is pretty much going to cost something. I don't drink bottled water, pop, etc... at home, but if it gets hot enough, and I can't scam some water, I may end up buying 10 dollars of gatorade.

There may be offset items that you don't do at home. Like if you are paying your own way in life, the rent is still payable, or taxes, but the food you would otherwise eat, or entertainment, eating out. Magazines, movies, are at the very least going to move somewhat to that budget item called your trip.

You can also go gear snob and sorta cheap out. Ray Jardine is a huge gear snob, but in his book he is ahead if he uses a poly tarp, rather than a tent. Look at his various bike trips at rayjardine.com. He basically bypassed the whole touring thing, but going ultralight with one bag. And he uses cheap bikes, though that didn't always pan out for him.