rob (one) blind
To steal everything someone owns, especially through deceitful or fraudulent means. Sometimes used to insinuate that someone is charging too much money for something. The CEO was sent to prison for robbing his clients blind through a complex Ponzi scheme. Another $100 in fees? These guys are robbing us blind!
ˌrob somebody ˈblind
(informal) get a lot of money from somebody by deceiving them or charging them too much for something: He robbed his clients blind, taking about 25% of their profits.