Launch without billing. You can implement that later. "Free while beta! Early adopters will get a special discount!" Make sure you are breaking up work into sm

Launch without billing. You can implement that later. "Free while beta! Early adopters will get a special discount!" Make sure you are breaking up work into small releasable steps. You should get the "oooh ahh" feeling of tangible accomplishment at least a couple times a week. Get users as quickly as possible. As soon as you have one real user, it suddenly feels like you're participating in the real world instead of working in a hole. Announce changes to your users; positive feedback from them is emotionally buoying, negative feedback is an opportunity to fix what you just broke. Create a facebook group/mailing list/forum/whatever for your early adopters. The community will help motivate you. Spend time refactoring. Whether or not the investment will pay back with more productivity is irrelevant; clean code improves your quality of life and makes you look forward to work and that alone makes it worthwhile.