The most common way to accept vendor registration payments is through Stripe. It handles transactions securely, sends receipts automatically, and makes it easy to issue refunds if there is a dispute.
Some organizers use Zelle, Venmo, or Cash App, but those are harder to track and don't give you the same paper trail as a payment processor. Marketlly uses a Stripe integration to accept vendor payments, lets you set different booth prices for each market, and keeps everything manageable from one dashboard.