2nd hand CF shaft advice

I’m in south east Asia so needless to say it’s hot and humid. I currently have a cheap wood Rhino cue I got as 2nd hand as well and plan on using that butt. The shaft is slightly warped and dinged up so looking to get a 2nd hand CF shaft but want to stay under $250 USD if possible.

What should I look for when getting 2nd hand CF shaft?

I know to watch out for fake CF so is there one in my price range that’s real CF?