What is the best way to build an app end-to-end for someone looking to release an idea to the world from scratch as a hobby?

There is not really any such thing as a "best way", there are just good practices that suit your needs and your experience. If you are looking to build a web app, and you have no experience in other web technologies, I would recommend Groovy/Grails.   Not because it is the best (although I might make that argument, too), but for someone with little experience, it is probably the easiest to get up and running with a real-life app.   It takes care of a lot of the fiddling associated with web apps, and gives you a quick start.     If you want to get fancy, add Twitter Bootstrap and AngularJS.   Angular has a steep learning curve, but does a lot of amazing things. If you are talking about a phone app, you'd have to decide whether you are supporting Android or IOS or both.   If you choose Android, the official Android Development tutorials are excellent. All of the software I mentioned here is free, but you will have to pay for a few things here and there, most notably, a web provider. Your question 1 and 2 are a bit vague considering you have given us no context whatsoever.