Aduana disservice at the airport.

What is the dollar or peso limit on items a non citizen can bring into Mexico ?

Is the tax level different for a permanent resident returning with some household items?

https://consulmex.sre.gob.mx/montreal/index.php/en/foreigners/services-foreigners/407-what-objects-can-i-bring-in-my-luggage-to-mexico

I think beyond the items listed in the article you are allowed to bring $300 of items duty free.
Above that I think it's somewhere between 15-20% of the 'overage'.
I've been taxed twice:
Once when I brought in a second computer- they found a comparable listing on eBay and charged me $50
The second time when I brought in an eBike valued at $999USD.