Ok so found out that you can edit the game files with notepad or wordpad, BATTLETECH\BattleTech_Data\StreamingAssets\data\simGameConstants\SimGameConstants.json here you can edit the starting money "StartingCBills" to what ever you want but dont exceed the maximum value the game wont start i change it from 980000 to 980000000
there you can edit more stuff but keep in mind max value for everything have fun.
980000 to 980000000 work like a charm
also modified the starting mech to:
"StartingLance" : [
"mechdef_atlas_AS7-D",
"mechdef_atlas_AS7-D",
"mechdef_atlas_AS7-D",
"mechdef_atlas_AS7-D"
Basically the 1st mission after 3 years thingie I started with 1 blackjack (my main) and 3 atlas (my lance) and 1 atlas in garage.
NOTE:
1. For all of this to work, you MUST start a new game, I tried loading early saved game after I modiefied the "SimGameConstants.json" but the game just loaded with the old setting.
2. After restarting a new game, the changes (mech) appear during the 1st mission "3 years later thingie" and the money appear once you're able to control the dropship interface.
3. Just in case after I played a mission or two, I replaced the modified "SimGameConstants.json" with the original one and the changes in the savefiles stays (just to avoid any inconsintency when steam or paradox are checking the files integrity....if any)
4. Just in case ... I did everything in steam offline mode and not logged in at paradox account.