$15/hr for "I'm building a service that should entail a production ready app in iOS, Android, website, and server setup as well as website/app design and logo creation and branding all by myself"
YES, this company is using you for cheap labor
YES, this company is using you for cheap labor
For what's it's worth, I think I made like $12 in college updating crappy php college websites. It was fine, gave me some resume material. Gotta start somewhere.