Giveaways as marketing?
I've recently done a book giveaway for my website https://tuthub.io where people could win one of 8 programming books by posting to the website. I got a lot of participants and a nice boost in signups. I have an existing audience on Youtube (https://www.youtube.com/c/codinginflow) so it was easy for me to promote it there.
What do you think about giveaways/raffles in general? People like winning stuff and you don't have to pay a ton to get people to participate. I even consider doing it as a regular thing for people who post resources to my website.
I believe it can be a really powerful tool, especially if you make sure you're learning more about your product and potential users with this flow of people.