Hi! A friend of mine said he heard some people saying "This dress is too much expensive." or "This flat is too much cheap." I have learned "This dress is too expensive." or "This flat is too cheap." only. Can anyone verify for me please? Thank you!!! (^_^)
Hello BiR

You could say 'this dress is much too expensive', or 'this dress is too expensive'.

'This dress is too much expensive' is incorrect, though it's possible a native speaker would say it for (supposedly) humorous effect.