I understand the concept of opening a payment channel were you commit with a fixed amount of BTC, transfer freely between parties, then broadcast to the network. I also understand there will be a minimum amount to of BTC to open a payment channel.

What happens if you just have enough money in your whole balance to buy a coffee for, let's say, 0.00001 BTC?

If you have to use someones elses payment channel to get through, how is it decided how much fee are you paying the channel owner?

If you can't spend small amounts, then how will it solve micro-transactions, or having unusable wallets with amounts smaller than fees?

Thanks!