Pre paid sim card for 16 days

I will spend 16 days in Japan and would like suggestions on how to access the internet these days. I researched on the pockets wifi but found it all very expensive. Is there a cheaper option? Would be two devices and only data.
I appreciate any help.
PS: We are brazilian tourists!

There are many prepaid SIM card providers; have you done a Google search?

What devices do you mean?
Smartphone, tablet?

Slightly inconvenience, not always on connection but cost you nothing, will be to use the free wifi available at some train station, cafe or convenience store. Those normally limited to 30mins usage per connection.
Most hotel also provide free wifi.

For smartphones, you can get prepaid sim for 1 phone and let the other one thether. Prepaid SIM Data only cost from 3,xxx yen for 14 days, 30days etc.

I googled it, however there are too many options and I don't know which one will suit me better.
I will use on smartphones.