Salaries range from $62,000 for a senior account executive at finance-focused Prosek Partners to $420,000 for a managing director at consulting firm FTI Consulting.
Edelman, the industry's largest firm, paid a VP, tech and media specialist up to $155,000.
Nick Tran, TikTok's head of global marketing, said the campaign is meant to differentiate TikTok from other social-media platforms, grow its user base, and build better brand recognition.
The ad push comes as President Trump issued two executive orders asking TikTok to sell its US operations to an American company.
Data from ad-tracking firm MediaRadar shows that Amazon has spent 70% more year-over-year on promoting its retail business since May.
Instagram in particular has benefitted from Amazon's ad spend. Amazon spent $22 million on Instagram ads in July, up from $9 million in May, according to data from Pathmatics.