Fees aren't fixed per block, and they're also not a percentage. Exchanges and Bitcoin software suggest a fee that ensures a quick confirmation, but you can choose whatever fee you want. Transactions with a higher fee are prioritized by miners, because then they make more money. Coinbase always uses a really high fee (around $3.50), so your transactions are always confirmed as fast as possible. I made a few transactions recently where I set the fee to $0.20, and it just took a few hours before it was confirmed.

So if it's not urgent, you can send $2 million USD with a fee of $0.20.

Parent was saying that you can lower your percentage by raising your transaction size.

The fee is not fixed but what matters is the size of the transaction (in bytes) and not the amount. So normally it's cheaper to move 1 thousand BTC from a single address to an other than 0.1BTC from 10 addresses to 20 others.