Yes, the minimum is 80 agents. The Enterprise plan is a flat fee ($3,999 per month billed monthly, or $3,199 per month billed annually) that includes 80 agent seats, which are pre-purchased as part of the plan.
If you have fewer than 80 team members
If your team or company has fewer than 80 people, you can simply leave the unused agent accounts as dummy accounts, for example for future team members.
Adding more agents
You can add more agents above the 80 included for $49 per month each ($39 per month each on annual billing). See also LiveAgent invoicing explained for billing rules that apply to the extra agents.
Enterprise or Business?
If your team is smaller, the Business plan has no agent limit and is billed per agent. Enterprise costs less than Business from about 68 agents on monthly billing, or 66 agents on annual billing. You can compare all plans on our pricing page.
Are you on the Legacy Enterprise plan?
The earlier Enterprise plan is now called the Legacy Enterprise plan, and it has no minimum number of agents. See Is there a minimum number of agents for the Legacy Enterprise plan?