I built an Alexa app a few years ago for an Amazon-sponsored hackathon. Apparently it has a bit of a user base still, and for some reason Amazon sends me about

I built an Alexa app a few years ago for an Amazon-sponsored hackathon. Apparently it has a bit of a user base still, and for some reason Amazon sends me about $50/quarter. I don't know how the app is being monetized, it certainly wasn't something I did. Also, because my app uses API Gateway and Lambda as a backend, Amazon gives me a $100 credit on my AWS account every month to cover the costs. My costs for the app are about $10/month, so the other $90 are used for various other activities.