Current value -- if the vehicle is totalled, in other words, if the cost of repairs exceeds the current value of the vehicle. Otherwise, the cost of repairs. That's the law here and I'd assume it's the same for bicycles as for cars.

And I've agreed to be paid outside of the "red tape zone" before. It's much kinder, I think it creates good will and it's still enough of a PITA for the offender that, with a little luck, they learn to be more careful.

Maybe I was wrong to say the OP should ask for $500. I'd assumed bike or damages was worth that much, but if the cost of repairs (or total value of the bike) is only $300, then that's what he should ask for.