I don’t even make 10,000 searches in a year. I just did a search of my browser history: 8881 visits to DDG in the past 12 months, including many duplicates where I hit the back button to click a different link on the same SERP.
How much do you think it would be reasonable for them to charge for 10,000 searches? I assume this fee is supposed to sustain the company and fund all development and growth with a 100% ad-free business model, forever!