Overall, your sentences are correct. Here are just some corrections, which could make them read more native: 成本 - 我不在乎你需要做什么，你要做吧，成本无所谓！ Comment: 你要做吧 -> (如果) 你要做，就去做吧. There is no ambiguity if I read it within the context of the whole sentence, but it is good to be more specific so reader doesn't have to think hard. 免签 - 你可以免签进去一些国家。 comment: 进去->进入. Visa is something you need to have when you ENTER some country, so 入 could be more appropriate. 宽容 - 我们都应该努力对别人的信仰和习惯宽容。 Comment：-> 我们都应该努力接受别人的信仰和习惯. "宽容" is more used in accepting one's negative behaviors, but here "信仰和习惯" are neutral words. 勤劳 - 他很勤劳，25岁之前就变成百万富翁 Comment：变成->成为. The latter one implies that he worked hard, while the former doesn't

你做得很好，都没什么问题，语法和说法习惯也像中国人。就“烫衣服”，我认为大部分中国人会说“熨衣服”，至少南方人是这样的。 希望能帮到你。