A Note on Cheats
To perform these cheats, you'll need to go into certain files meant for the game, so back them up in a different file folder before you do anything.
Tons of Money Cheat
Is that opening total of $33 not enough for your rocking needs? Make that grow quite a bit by using the starting-cash cheat. Go into the "Rock Legend" folder under "Program Files." Then, go into the "Data" folder to bring up the game's configurations. Here, open the "config" document, which has the game's opening configurations. Scroll down to the bottom of the document. There will be a line of text that says "RS_STARTINGCASH = 33.00." Change that number value to whatever amount you want. You can go as high as 999999.99.
Other Cheats
Now that you have the config document open due to your need for more money, you can monkey around with the file for even more benefits. Under "GAME_DURATION_YEARS = 5," change the length of the career mode. Continue moving on down, and each value in the file is accompanied by an explanation of what it does. Want to ensure that your song becomes a classic? Change the chances under "RS_CLASSIC_SONG_CHANCE" from .38 to .99. Want to become a better songwriter faster? Change the value on "RS_SONGWRITING_PER_SONG" from .1 to .8. Finally, to get a bigger cut of each album sale, change it under "RS_ALBUM_ARTIST_SHARE" from .78 to .99 to take almost all of it.