What is the highest altitude the ISS can raise itself to? What about with help from Progress-MS? How much would it cost to raise the ISS by 1km with or without progress?
The ISS is designed to operate between 330-435 km. It could be raised to that level if required to by the on-board fuel, or perhaps even higher, but that isn't typically done. The altitude is set to optimize the fuel cost. It takes more fuel to reach the station if it's higher, but it overall requires less fuel. The exact amount of fuel for the various propulsion modules can be found on the ISS Propulsion Module Wiki page. The space station needs about 7000 kg of fuel per year, and loses about 90 m/ day. Given all of that, the ISS needs to use about 210 kg of fuel to raise the altitude 1 km. At any one time, it can raise the altitude about 30 km, although that would hit into reserves that are preferred not to be used.