Stable income: Somewhat stable

Selling old textbooks can provide a moderately stable monthly income for most people. Based on online research and common experiences, individuals can generally rely on consistent earnings, although there may be fluctuations due to demand and seasonality. While it may not always be as steady as a traditional job, many sellers are able to generate a decent baseline income over time. Setup costs range from $0 to $50, with profits typically realized within 2 weeks of listing. I'd rate it a 3 out of 5 because while it offers a reliable income stream for many, there are occasional fluctuations that may impact monthly earnings.