Steambot Chronicles, or Ponkotsu Roman Daikatsugeki: Bumpy Trot as it was originally named in Japan, is a Playstation 2 game developed and published by Irem in Japan, Atlus in North America, and 505 Gamestreet in a few countries in Europe. There is also a spin off on PSP named Steambot Chronicles: Battle Tournament, and an odd tie-in puzzle game on PS2 and PSP named Blokus Portable: Steambot Championship (one of only four games published by Majesco on the PSP in the USA).
A quick look at the back of the case of Steambot Chronicles shows the game being marketed as an open world RPG, and that is correct in a way. The game starts off as linear as any other RPG that's been made and then opens up. It's similar to the opening dungeon in Elder Scrolls, but drags on much longer. In this long opening sequence, you'll visit all three of the main towns, many of the back areas, and explore most of the world by the time it's completely opened up. Once an area is open, it may be visited at any time afterwards, and as a result, money can be hoarded this way.