"Most of the time," the spokes-technician says,"the repair is no cost to you."
I don't those ads annoy me so much.  I want them to say at no cost.
It's not the "to you/" If they said, "To you, the repair is no cost", it would sound equally wrong.
But it doesn't sound wrong to say "the repair is $5" or "the repair is free". I appreciate the fact that they're saying they settle for what the insurance company pays, rather than saying it's free, so I should like them saying what they do.
So why that "missing" at bothers me, I can't say. Does it bother anyone else, or have I taken another step towards being completely unhinged?
Either way seems alright. Â I seem to hear more of 'at...cost...' Â in adverbial phrases:
At great costs, they took the hill.
At no cost to you, we'll throw in a 12-month membership.