Keep in mind that the prices are variable:
+ $0.20 ICANN Accreditation Fees (variable)
+ $6,86 .com ; $4,98 .net , $6,65 .org Verisign (variable)
= 7.06 Total pr. .com domain name.
The registrar you sign the domain name with get all above that.
Additionally the registrar also has to pay for the ICANN Accreditation:
+ $4.000 yearly ICANN Accreditation Fee
+ $1.500 yearly ICANN Variable Fee
+ $500 insurance
= $6.000 Total Yearly