Hi,
There’s no cost for activating Corvid or implementing IDX on your Wix site. However, there may be a fee for the IDX software you plan to utilize.
You may want to take a look at the fetch API along with instructions on how to get started if the software provides the endpoints.
You can also try syncing your data with HTTP functions using cron or a similar scheduler that connects to an MLS server using the RETS protocol. Checkout this GitHub for more information.
Hope this information helps!