It can be a challenge, but there are several strategies you can consider. Here are some options:

1. Airdrops: Some cryptocurrencies are distributed for free to users who $BNB meet certain requirements. Stay tuned for airdrop announcements on Binance and participate in them.

2. Staking: Binance offers the option of staking for certain cryptocurrencies. By staking, you can earn rewards in the form of interest for holding your cryptocurrencies on the platform.

3. Binance Earn: This service allows users to earn interest on their digital assets. You can deposit cryptocurrencies into flexible or fixed savings products and earn interest on them.

4. Referrals: Binance has a referral program where you can invite friends to register on the platform. If they trade, you may receive a commission.

5. Participate in promotions: Binance often organizes contests and promotions where you can win cryptocurrency prizes. Check the promotions section on their website.

6. Education and rewards: Sometimes, Binance offers rewards for completing educational courses about cryptocurrencies. You can earn tokens by learning about the crypto ecosystem.

7. Trading: Although it is not 'free' in the traditional sense, if you have trading skills, you can try trading with small amounts and look for opportunities to increase your funds.

Always remember to research and be cautious with cryptocurrency investments, as they are volatile and can involve significant risks.