Game Cheats:
This cheat involves editing your SAVE GAME FILES --- So back it up!!! SAVES are usually found in C:\Users\(User Name)\AppData\LocalLow\rondomedia GmbH\Roadside Assistance Simulator\Save ...
Using HxD (or ANY free File Hex Editor Program), search the save file for BUDGET. The first instance should show something like this "reservedBudget.." .... Next, select the cell that holds the letter T at the end of the word Budget, count 3 cells right and THAT is the cash you currently have on hand .... I stumbled across this with 8 cash ... Work up to 8 cash so that you have in the 4 cells something like FC FF FF FF ... The game I guess saves the cash in reverse order, so you actually LOWER the 3rd cell hex value to get a higher value in cash.
The next 2 or 3 cells after the 3rd cell are multipliers for the 3rd cell. so LOWERING those is what will multiply the 3rd cell when the game reads your save file to determine your cash.