To be honest, this is not the most fun part of your production.
P-1 visas (Performance Visas) are required in the United States for any foreign act performing a gig “for hire”- meaning that they are getting paid directly for their performance.
HOWEVER- if the act is performing for an engagement that is considered a cultural event and the gig is for gratis (free) then they do not need to obtain a performance, only a regular tourist visa.
If you can position the performance in an ethical way in such that the artist you are presenting doesn’t require a P-1 visa, then you are looking to save between 3-4,000USD as this is what it actually costs per band to organize a performance visa using a trained immigration lawyer or visa expert.
The bottom line is that if you are presenting a one off performance, you should take into account a minimum of $150 per artist for a regular tourist visa, and up to $4,000 for a P-1.
This isn’t something you can avoid unless you are doing a package deal.