If you self insure (as you apparently did) you have to make good on the sale. It's not up to the buyer to pay for insurance. I think ebay even prohibits implying the buyer decides on insurance in your listing.

If you know and trust the buyer (maybe because he bought from you before or he's a Club member) self insurance is the way to go. Otherwise, you may want to pay the carrier for insurance.

I seem to recall that PayPal is offering a limited amount of insurance free if you ship through them and send it USPS Priority. You'd have to check on-line for details. Priority is 4 times as much as 1st class for one chip, though. Not worth it, in my opinion for chips valued under several hundred dollars.