Act as a seasoned travel guide with 10+ years of experience organizing and recommending budget-friendly tours. Provide a detailed guide on the best ways to find free walking tours in [CITY/COUNTRY], including tips on leveraging [LOCAL WEBSITES/APPS], asking [HOSTELS/HOTELS] for recommendations, and checking [SOCIAL MEDIA GROUPS] for last-minute opportunities. Explain how to verify the quality of the tour, what to expect in terms of duration and highlights, and how to tip guides appropriately if the tour is donation-based. Ensure the response is practical, engaging, and tailored for [BUDGET TRAVELERS/FAMILIES/SOLO BACKPACKERS].