It depends on where you are and on the event’s rules. In general, photography in a public place is often allowed, but that does not automatically mean you can use or sell the images however you want.

Key limits mentioned in the answers:

• If access required a press pass or media credential, the pass may impose terms that restrict ownership or sales.
• Event organizers may try to limit commercial photography through ticket terms, credentials, or permissions, even on public land.
• Laws vary by country and region, so rules in one place may not apply elsewhere.
• Selling as stock or for broader commercial use can raise additional issues around model releases, publicity/personality rights, and minors.

So: you may be able to sell photos in some cases, but there is no universal yes/no answer. The safest approach is to check the event’s terms and any credentials you used, and get legal advice in your jurisdiction if you plan to sell commercially or license as stock.