https://www.pcgamer.com/metal-gear-survive-charges-money-for-extra-save-slots/

In an unusual move, Metal Gear Survive charges its players for extra save slots. First noticed on reddit and verified by us, if you want to create a new save slot beyond the first, you'll need to fork out "1000 SV Coins". SV Coins are an in-game currency which can only be purchased with real money.

Basically, once the 'New Game' option is clicked, and assuming one save game already exists, you'll be met with this message: