Unfortunately, it's not likely worth that much to a buyer - if someone had you do 50k worth of work, they would have gotten something custom-tailored to their needs.

By building this for yourself, you were trading that guaranteed income for the potential of this making much more than that if it caught on in the market. Whether it could possibly do that is an unanswered question ATM.

That said, good luck, I hope someone makes your day!