"if someone says make sure you leave at least 10 steem in your account at all time"
They mean 10 total Steem Power, or powered up Steem. You need about this much in your wallet or you can lose your ability to interact with the blockchain. That's $10 worth if Steem is $1, $50 is Steem is $5.
I hope that answers your (totally not dumb) question.
I guess I am a hopeless cause.