I'll be interested to see how they go about doing this. First, I think it's very smart of Tesla to separate the "free" charging from the base price of the Model 3. Some of the buyers who are mostly city dwellers may not travel all that much and will charge mostly at home, opting to buy charging as needed for the occasional road trip. Other who are road warriors will purchase the optional charging, as it will pay for itself over time.
I guess the only question I have is if the charging options are tied to the car or to the owner. If a first generation Model 3 owners decides to trade in that car a few years later on a newer Tesla, does the owner simply keep the contract active on the new car? Or, if that same used Tesla goes on the market, does the new owner of that used one have to take the car with or without the unlimited charging contract that the previous owner bought into? It would seem to make sense to unbundle the free charging option from the car itself. If the buyer of a new Model 3 invests in that option once and Tesla says it can stay with that owner, it's incentive for that owner to stay with the Tesla brand for the next car, and the next car after that . . . buy the charging for the lifespan of the driver and use it on a succession of new Tesla auto purchases across the decades. We'll see how it works out.
And, yes, it's my guess that the first Model 3s to hit the streets will be the more well-appointed ones, in the $45K to $50K price range. The folks who put their down payments on the base sticker ones will get theirs later. This, apparently, is how Tesla did it on the Models S rollout.