It cost Jim almost 2000 yuan in mending his old house 这句话说法有没有错?

这句话应该这样说:
He spent almost 2000 yuan in mending his old house.

给你详细解释下他们在用法上的差别
spend的主语必须是人，常用于以下结构：
(1) spend time ／money on sth. 在……上花费时间（金钱）。例：I spent two hours on this maths problem. 这道数学题花了我两个小时。
(2) spend time ／ money (in) doing sth. 花费时间（金钱）做某事。
例：They spent two years (in) building this bridge. 造这座桥花了他们两年时间

cost的主语是物或某种活动， 还可以表示“值”， 常见用法如下：
(1)sth. costs (sb.) ＋金钱,某物花了（某人）多少钱。
例：A new computer costs a lot of money. 买一台新电脑要花一大笔钱。
(2) (doing) sth. costs (sb.) ＋时间,某物（做某事）花了（某人）多少时间。例：Remembering these new words cost him a lot of time. 他花了大量时间才记住了这些单词。

it costs sb. doing sth.