How about some sort of remote consultation or Skype call in the $200-$500 range, perhaps combined with another reward level.
What about something like $5000-$8000, on-site consultation/assist on a build?
Make yourself as serene as a flower, as a tree. And on wednesdays, as serene as this tiny ad:
3 Plant Types You Need to Know: Perennial, Biennial, and Annualhttps://permies.com/t/96847/Pros-cons-perennial-biennial-annual