Don't register a company before you have something you're 100% sure you can sell. It's easy to spend a lot of money and get no return.
Once you're sure, by all means, register your company, but keep it lean.
We registered as soon as we'd brought in the first sale. It felt super scrappy trying to make an invoice that looked legitimate, but was fine in the end.
My close friend recently registered a company and he said the registration process sucks the fun out of running a business. It's not even a initial capital problem its more about how slow the entire process is. But now after 3 months of running around, he is very happy about it and says it felt a new learning curve in life.