For small packages and starting out, economy lines are the way to keep costs down while testing products. Some are definitely more reliable than others though. There's a pretty detailed guide that explains one of the popular options yanwen shipping and how it compares to others, you can read it here
https://easync.io/articles/yanwen-shipping-a-complete-guide/ . It breaks down tracking quirks and average delivery times which helps set customer expectations. Just remember economy means slower, so factor that into your store policies.