Here's a good existing thread on this topic, with links to relevant sites:
https://forum.mrmoneymustache.com/throw-down-the-gauntlet/bike-around-america/msg11328/My touring bike, plus panniers, racks, and million other specific components totals about $2000. The camping gear adds probably another $1000. That's all fairly high-end stuff though, and designed to cover just about anything the road can throw at me, so close to the maximum you could reasonably pay for a good loaded-touring set-up. A true Mustachian using Craigslist could surely accumulate a reasonable touring setup over time for a fraction of that.
Once you get yourself in bike-riding shape (riding around town, commuting to work (touring bikes make great commuting bikes), etc.), and get familiar with your camping gear (if you aren't already), the first step of loaded bike touring is to find a campground a reasonable distance from your house (40-60 miles), and on a nice weekend, ride there, camp overnight, and then ride home. From there, it's just a matter of stringing multiple days like that together.
1) Start riding locally and get in shape. Don't underestimate this: I
"trained" for my first long tour (many years ago, when "10 speeds" were the epitome of bike tech) by riding up to 10 miles on flat land. I discovered that this was woefully inadequate for riding through the Sierra Nevada.
ha, I just finished a month-long ride through the Sierras last week, and I don't think there's *any* riding you can do to fully prepare yourself for those mountains! But yes, 10 flat miles is a particularly woeful amount of preparation. :-)
As I noted in the above thread, my bike tours have never ended up being particularly inexpensive, and even though this was my first post-MMM tour, the expenses didn't change much. $8 beer? $17 for 3 slices of pizza? Sure! But a lot of that is because I usually end up packing too much activity into a relatively-small 4-week window of vacation time, especially this one, so I quite frequently find myself willing to trade money for time; I could probably do a lot better on a post-retirement trip where I could afford to spend more time and energy to make more economical decisions.