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A weird adverb

A weird adverb

Confused
Hi,
does it exist the adverb "costlily"?To be honest it looks to me a bit strange!Actually I haven't ever heard of it.
I looked up at the dictionary but I only found the adjective "costly". Maybe it's not in my dictionary but anyway this gave rise to the question I am going to ask you.
Is it always obtainable an adverb per each adjective by adding "ly" at the end of it or sometimes you can make a mistake using unscrupulously this "-ly" rule?

Bye Wave

EL