All of these answers are important, but before doing any of that, first consider validating your idea. That means getting customer feedback outside of your circle of family and friends. Funding can certainly speed things up but it also means you lose some control over the vision, the pace and the deliverables. The sooner you get funding the more likely it is going to cost a higher portion of your equity. I'd consider going as far as you can without funding first, if it's possible.

Bottom line is that you shouldn't go far into building your product, and certainly shouldn't spend more than a few dollars before having some solid customer validation on the concept.

Depending on yur location there may be some grants available for early stage validatioin of your concept without having to give up too much control or ownership.

My Startup is just about to launch our flagship product on the Google Playstore and so far we have not pursued investment. We are all (including the programmer) working for equity (part ownership).