Hi
Yes, you are right. You have to pay 75$ plus 490$.
Please read:
http://www.cic.gc.ca/EnGLIsh/information/fees/fees.aspIF the child is under 22 the fee is $75 sponsorship, $75 Application fee, total $150
As the the child (I assume is a dependent of the sponsor) no RPRF is required.
" The following applicants are not required to pay this fee:
*
dependent children of a principal applicant or sponsor, a child to be adopted, or an orphaned brother, sister, niece, nephew or grandchild; and
* protected persons, including Convention refugees.
PMM