it says I have an active subscription on “Apple Cash” even tho I’ve never used it in my life I’m just trying to use my apple balance as in iTunes gift card to purchase In game items, won’t let me not even letting me download free apps, help please

Apple account Balance is used automatically before any other payment method.

Apple Cash, is not a subscription, it is a digital debit card offered by Apple, you will always have it because its generally turned on by default, but you don't need to use it, and your account balance should be used before it.

Verify you don't have any other payment method besides those 2 added to your account by following the steps in support document linked below.

click here ➜ If you need to change or update your Apple ID payment method - Apple Support

Also make sure you have enough money in your account to cover the purchase plus any applicable taxes.

If the price is $9.99 and you have $10 in your Apple account balance, it won;t be enough for the purchase unless you live in a place that does not charge any sales taxes.