The cost of hire a full stack developer can be vary based on few factors, includes where they locate, skills, experience, & the specific full-stack development company you choose. 

US:

Junior: $61K - $80K/year

Mid-Level: $80K - $120K/year

Senior: $120K - $180K+/year

India:

Junior: $10K - $20K/year

Mid-Level: $20K - $40K/year

Senior: $40K - $60K+/year

Eastern Europe:

Junior: $15K - $30K/year

Mid-Level: $30K - $50K/year

Senior: $50K - $80K+/year

South America:

Junior: $10K - $25K/year

Mid-Level: $25K - $45K/year

Senior: $45K - $70K+/year