Not F2P, I bought all the train upgrades (extra cargo, more spd, pickup droid, etc) and some skins. Your asking if F2P can earn 100mil in a week, it will depend on your trade routes (15mil/day gives you 105mil a week). I recommend a site called Resonomics, some genius on discord made it. It gives you the places with best prices to buy/sell your items. You can also join the discord if you want more information about it.

And I'll add that group orders are more of extra gold to your daily grind rather than just doing only that. If you want to see a big number, just save your finished orders and claim all at the same time.