Bù zhídé wèi zhè zhǒng rén báisòng zìjǐ de shíjiān.
It's not worth giving your time away for free to people like that.
Tips
usage
白 in compounds often means 'for nothing / in vain,' as in 白费 (to waste) and 白干 (to work for nothing). 白送 means giving something without receiving anything in return.