The cost to mail a letter depends on the country and the type of letter: In the United States (USPS rates):

• Standard-sized, rectangular envelope stamps start at $0.73 for letters up to 3.5 ounces.
• Postcards start at $0.56.
• Large envelopes (flats) start at $1.50

In Germany (Deutsche Post rates as of 2025):

• Standard letter up to 20 g costs €0.95 (increased from €0.85).
• Compact letter up to 50 g costs €1.10.
• Large letter up to 500 g costs €1.80.
• Maxi letter up to 1 kg costs €2.90.
• Postcards cost €0.95 (increased from €0.70)

For international letters sent from Germany:

• Standard international letter costs €1.25.
• Postcards cost €1.25.
• Larger formats and registered items have higher fees (up to €17.00 for maxi letters up to 2 kg)

In summary, mailing a standard letter domestically typically costs around $0.73 in the US and €0.95 in Germany as of 2025. Postcard rates are lower, and larger or heavier letters cost more depending on weight and size.