"Should take the money when a beta user offered to pay"
Not sure about this point. Why would we take money if we knew the product is not in a working condition. And what if, the product doesn't get to a stage where we feel the fee justifies.
I get your feelings here, and I think they say good things about you. But until you take money, you aren't running a business. What with business cards, a nice website, and an office, it might look like a business, but it's just an expensive fantasy.
Money is proof that your customers find you valuable. If you are really worried that the money is more an expression of faith and that you might not earn it, then don't recognize the revenue. Keep the money separate so you can give it back if things don't work out. But take the money. And then ask other people for money.
Avoiding taking money is basically avoiding finding out whether or not you've got something good. Your answer to that question is almost irrelevant. It's your potential customers that you should be listening to. One of the truest answers they will give you is their first check. (Still truer ones are regular checks and referrals to friends.) So take the money.
The nice thing about paying customers (besides the money) is that they will tell you what's wrong with the product, so you can fix it. Nonpaying users are much more likely to just walk away.
Not sure about this point. Why would we take money if we knew the product is not in a working condition. And what if, the product doesn't get to a stage where we feel the fee justifies.