Your Sling Account has limits on how much money you can deposit and withdraw per week and per month, as well as how much you can spend on Sling Card per day.
There's no limit to how much money you can hold in your Sling Wallet. Or to how much you can send to someone else on Sling.
How to view your limits
Tap your profile picture at the top left of your home screen
Tap 'Limits'
Here you'll see your overall limits, as well as how much you have left for the week or month. View limits for deposits to Account Details.