How much does the Affidavit of support cost?

Excuse me, I'm curious about the cost associated with an Affidavit of Support. Could you please elaborate on the specific fees or charges that I might encounter when obtaining this document? Is there a standard rate across different jurisdictions, or does it vary depending on the location and circumstances? Additionally, are there any hidden costs or extra fees that I should be aware of? Your insights would be greatly appreciated.