What makes a good question to pay for?
One specific situation, the detail that makes it yours, and the decision you are stuck on. Specific questions get long, usable answers; "any advice?" gets a paragraph.
The shape that works
Say what is happening, what you have already tried, and what you are deciding between. Three sentences of context change the answer more than any extra payment.
Ask one thing
Five questions in one submission get one answer split five ways. Ask the one that unblocks the others.
60 answers in the Nudge help centre.