How to develop a web application?

What level of investments do I need to develop and launch a social web application?

• Now for some more specifics: I am a healthcare professional with a full-time job, and hesitant to leave the well paying job at this time to pursue my startup ambitions (think I have a decent idea, but don't want to 'risk it all' before I see potetial/initial success in the real world). I spent the last 4-5 months, 15-20 hrs a week, learning PHP, JavaScript, CSS, HTML, etc. and even though this does not make me an expert, I think with another 7-8 months of dedicated efforts, I should be able start coding  my web application (with some struggle of course). My question is: if I do not have any employees and the associated overheads (will code myself, and get a contractor to help me with designing the look-and-feel of my web application, since this is not my forte), what costs am I looking at for launching and maintaining my startup (e.g. server costs, hosting services, social media marketing)? And what are some of the ball-park estimates of these cost elements? Based on my own research, I understand that scaling up an application could be a big challenge, but is this not something I can learn on my own? Am I being too ambitious?

• Answer:

  Have you tried researching existing solutions ( social site templates ) rather than building one from scratch? Remember it always takes a lot longer than you think. Also, have you validated your idea? Talking to potential users can give invaluable amount of insight, almost all startups morph and deviate from the original model. You're smart not to quit your job, another smart thing would be talking to an expert on Clarity, someone in the healthcare field, a successful entrepreneur who's already been there and done that, some of them are pricier than others, but in my case, it was the best $75 I ever spent in my life. Good luck