The latest USPS postage rate increase will take effect beginning on January 27.  I modified my shipping prices to reflect the new rates.  There is very little change in the US rates, but unfortunately, there was a significant jump in international shipping costs. I am always happy to combine items to ship flat rate when that will save you money.  An example of the rate increase is the padded flat rate envelope.  Internationally, it was previously $16.95 and will now be $23.95.  Sorry I don't have better news.
https://www.usps.com/new-prices.htm

~Sue