General

You have to pay tax for each transaction you make unless the total cost for each transaction is below 100k mesos (99,999 mesos is below = no tax). In your example (unless you forgot a digit), if the 5000 items are bought one by one for 10k each then you don't pay any taxes at all. If all the 5000 items are bought with one transaction then you get taxed at 2,50% which is 1.250.000 mesos.

If you meant to type the items cost 100k each, and if the buyer buys the items one by one you will pay 0.40% tax for each transaction (400 mesos) x 5000 = 2 mil mesos tax.

If it happens with one transaction (100k x 5000 items = 500 mil) the tax will be 3% (15 mil mesos tax).

you get taxed for 50m

...you get taxed for w/e amount of money was given in total for 1 purchase based on the tax chart.

So, if someone bought all 5000 items at once, w/e they paid will match that tax amount in the chart.

Not in maple atm so idk the exact rates.