To highlight our company's benefits, we write short statements like "3 times less rate" or "3 times lower rate". Are these correct? Or do such forms require comparison to something else—for instance, "lower than standard rate"?
Similarly, if we use the phrase "[a competitor] spends n dollars, we spend half as much", can we end on half as much without appending a second 'as' phrase?
Kris answered the first half. Let me answer your final question. "Company X charges $1000, we charge half as much!" is fine. The obvious meaning in context is that you charge half as much as Company X. You could say, "we charge half as much as Company X" or "we charge half as much as they do", but it's not necessary. If you mentioned several other charges before so that it could be ambiguous, then you might need to clarify. Like, "The average charge is $100. Company X boasts that they charge only $80. But we charge half as much!" Now it's not clear if you mean half of $100 or half of $80.
"3 times less rate" or " 3 times lower rate"
is to be avoided in any case. Remember, times implies multiplication, not division. It should not be used in cases of reduction. It seems to be so common (?mistake) these days that people have almost accepted it and presume to be correct.
half as much is a different matter and is fine, with the as, which cannot be omitted, because that could mean half-a-dollar, not half of n.
