is this great service free or is there a limited number of downloads

Hi there!

Yes, downloading symbols & footprints on SnapEDA is 100% free, with no limits.

The only thing we charge for is 24-hour model requests if a part isn't yet available on our site (InstaPart: www.snapeda.com/instapart or via our subscriptions). But if the part is already on the site it's free. We're adding new parts daily too based on these requests, which everyone can then download for free thereafter.

Hope that helps clarify. Let us know if you have any other questions!