HELP selling an item - is this a scam!?

[natce-7846]

Hi all

I'm selling an item for the first time, from Australia (it's a laptop) and someone has purchased from America. 

When I sent the person a payment reminder they responded as below: 

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I asked him what he meant then he responed with:

REMOVED


Regards.

I have since sent him a message tell him about shipping costs. It's basically $90 without insurance or $145 with insurance (both tracked and signature). Does this look like a scam? Should I send him an invoice and if he pays, is that all legitimate?

Any help would be appreciated.

Cheers

Nathan