First-time home buyers often make avoidable mistakes that can lead to costly consequences. Key errors include not preparing financially, failing to get preapproval for a mortgage, and buying a home beyond their comfort level. It's crucial to consider all costs, including closing costs and hidden expenses of homeownership. Buyers should also explore assistance programs and various loan options like FHA, VA, and USDA loans. Lastly, maintaining a realistic perspective on home expectations and avoiding new credit applications before closing are essential for a successful purchase.