Semi-postals cost the same
According to USPS News Link, the Breast Cancer semipostal stamp has raised more than $47.9 million for research from the sales of more than 678 million stamps. The Stop Family Violence semipostal has raised nearly $2.3 million for domestic violence programs from more than 34 million stamps sold.
Each stamp is good for the First-Class single ounce rate of 39 cents.
For more on the law regarding semi-postals, click here.