The prices are already high, but will be raised still higher/further/more.
Is that correct?
First of all, thanks for your answer. I think your suggestion is very good. However, I need to write a sentence using the word "raise". Could you help me?
"Prices" has reference to the prices of housing. Would you still write it without the definite article?
Do you just want to write any sentence using that word, or does it have to be about house prices going up?