small potatoes
noun [ plural ] US informal uk/ˌsmɔːl pəˈteɪ.təʊz/ us/ˌsmɑːl pəˈteɪ.t̬oʊz/ (UK small beer)
无足轻重的事物
something that does not seem important when compared to something else
The insurance premium is small potatoes compared to what we'd have to pay if the house burned down. 同房子万一被烧毁时我们的损失相比，保险金就微不足道了。