A Google search does not show a recent postage increase.

And the current Notice 123 Post Office Price List (effective since Jan 2018), shows $3.50 for light first class packages. It costs $2.66 if you print your own postage labels (like through PayPal). But costs $3.50 at post office window:
https://pe.usps.com/text/dmm300/Notice123.htm#_c037

Robert
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my web page: gambling scenes in movies: http://www.antiquegamblingchips.com/StillsA_TopMaleStars.htm