If something sets you back a certain amount of money, it costs you that much money. In 1981 dinner for two in New York would set you back £5. see also setback. An offensive back who lines up behind the quarterback
If something sets you back or sets back a project or scheme, it causes a delay. It has set us back in so many respects that I'm not sure how long it will take for us to catch up There will be a risk of public protest that could set back reforms