Howmuchdo you want?
Howmuch可以直接做宾语成分。
我想表达：你买了多少个？
可以用Howmanydidyoubuy吗？
百度都说howmany不可以做宾语成分的。
百度上说的过于绝对。how many一般应接名词或of短语，但也和how much一样，在乎义非常了解的状况下可以省略其后的名词，单独用作宾语或者主语。比如：
How many do you smoke a day? 你一天吸多少支烟？《柯林斯词典》
In terms of extra staff — how many will we need? 就额外的职员来讲，大家需要多少人？《牛津词典》
▲COCA中也不乏如此的例句：
How many do you have?
How many did you eliminate?
How many have they passed restricting freedom?
How many have blown themselves up on a bus in Tel Aviv? One? Two?
How many are willing to act on its behalf?
