Making money efficiently without significant time, effort, or brainpower investment often involves leveraging existing resources or skills. Here are some ideas:

1. **Renting Out Space**: If you have extra space in your home or property, consider renting it out on platforms like Airbnb or even to local businesses for storage.

2. **Selling Unused Items**: Declutter your home and sell items you no longer need on platforms like eBay, Craigslist, or Facebook Marketplace.

3. **Participating in Online Surveys**: Websites like Swagbucks or Survey Junkie offer opportunities to earn money by completing surveys or other simple tasks online.

4. **Cashback Rewards**: Use cashback apps or credit cards that offer cashback rewards on purchases you make regularly.

5. **Freelancing Services**: Offer services such as graphic design, writing, or virtual assistance on freelance platforms like Upwork or Fiverr.

6. **Dog Walking or Pet Sitting**: If you love animals, consider offering your services as a dog walker or pet sitter in your local area.

7. **Driving for Ride-Sharing Apps**: If you have a car and some free time, driving for platforms like Uber or Lyft can be a flexible way to earn extra money.

8. **Renting Out Your Car**: If you don't use your car often, consider renting it out through platforms like Turo or Getaround when it's not in use.

9. **Affiliate Marketing**: Promote products or services through affiliate links on your blog, social media, or other platforms and earn a commission for sales generated.

10. **Teaching or Tutoring Online**: If you have expertise in a particular subject, you can offer online tutoring or teaching services through platforms like VIP Kid or Chegg Tutors.

Remember to research any opportunity thoroughly before committing and be wary of potential scams. While these methods may not make you rich overnight, they can provide a steady stream of income with minimal investment.