dApp Project

I am a CS student and I wanted to set my foot into something new. So, I've recently taken up the blockchain technology and want to make a dApp for my college project. I want to take my time to research everything but my prof is rushing me to give him a final proposal. I would really appreciate some ideas for a project. I have sufficient time to learn everything required. But, I need to give a final proposal keeping the expenses in mind, which frankly, I have no idea about. I can't really afford to make a very expensive project, but I think there must be some ways around it. Any help would be appreciated!