Packaging on this is interesting – from pricing page:
How much will Figma Slides cost when it is generally available?
Figma Slides will be included in all Starter plans for free or can be purchased for $3 per seat/month on Professional plans, and $5 per seat/month on Organization and Enterprise plans.
Do I need to have a full Figma design seat to use Figma Slides?
No, you do not need to have a paid Figma Design or paid FigJam seat to use Figma Slides. You will need a paid Figma Design seat to use advanced design tools in Figma Slides.
How much will Figma Slides cost when it is generally available? Figma Slides will be included in all Starter plans for free or can be purchased for $3 per seat/month on Professional plans, and $5 per seat/month on Organization and Enterprise plans.
Do I need to have a full Figma design seat to use Figma Slides? No, you do not need to have a paid Figma Design or paid FigJam seat to use Figma Slides. You will need a paid Figma Design seat to use advanced design tools in Figma Slides.