Question: How to withdraw small amount of tokens?

Hello @matijarma ,
Welcome to the forum!

For L1 → L1 transfers you need ETH, there is no change.
For L2 → L2 transfers you can use STORJ tokens to pay fee, and this fee is 1/100 of the usual fee on L1.
For L2 → L1 withdrawal you can use STORJ tokens to pay fee and it’s almost the same in gas, as an L1 → L1 transfer:

This can be used to transfer tokens from L2 to L1 deposit address of the exchange.
The popular Uniswap still uses L1 transfers, so the fee is much higher to swap tokens.
You can consult with 15 Gwei | Ethereum Gas Tracker | Etherscan

Matter Labs (zkSync) working on integrations with some exchanges, so it could be possible to transfer tokens via zkSync directly.
Regarding registration fee - it could be eliminated soon.
Check announce of Matter Labs to launch the zkSync 2.0: