Yes, there are a few ways you can sell your credit card rewards to individuals or businesses through online marketplaces, forums or brokers. But, it’s not recommended.
Some credit card issuers and rewards programs have rules against selling rewards. For example, United Airlines has a prohibition of sale or barter:
The sale, barter or other transfer or attempted sale, barter or other transfer of any mileage, certificates, PlusPoints, awards, benefits or status, other than as authorized and/or sponsored by United, is expressly prohibited. Any mileage, certificates, PlusPoints, awards, benefits or status sold, bartered or otherwise transferred is in violation of the Rules and any accounts or Members involved in such sales, barters or other transfers may be subject to United’s Remedies. The acquisition, use, transfer or attempted acquisition, use or transfer of mileage, certificates, PlusPoints, awards, benefits or status that have been acquired by purchase, barter or other transfer in violation of the Rules may result in United’s exercise of United’s Remedies.
Instead of selling rewards, we recommend another option like redeeming for gift cards or donating your points to charity.