Can someone answer the following :
I am arriving by boat from Chetumal. I intend to purchase a new sewing machine and possibly some other new in box items in Mexico.
When I arrive at customs it just a simple procedure : The customs agent looks at the receipt and then taxes the new item(s) at various rates for each particular item. Makes out a bill. I pay it and off I go ???.
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And now lets talk about used items : say for example I go to a pawn shop in Canada and buy a used $500.00 chain saw for $100.00 and they give me a receipt for $100.00
Is the Customs agent going to tax me on the $100.00 I paid or declare it a $500.00 chain saw and tax me accordingly ??
Thank You in advance for your replies........

I think it really varies depending on who you get but someone else will probably have the official rules of what should happen.

Arriving from Chetumal - show your receipt, pay our duty, head on home.

Used goods - You pay on "value" - so if you get too good a deal you may pay on a value higher than your receipt.