Klaviyo prices its email plan by active profiles, and suppressed and unsubscribed profiles don't count toward that number. So the fastest saving is usually suppressing profiles that will never open, click or buy, including bot signups. Done carefully, it doesn't cost revenue.
Free tool: Drop in a profile export: dead weight, likely bots and the tier you'd drop to
Runs in your browser; your list never leaves it. Tier prices are a snapshot you can edit.
Import the list of addresses as suppressions, or bulk-suppress a matching segment. Then compare your new active profile count with the plan tiers: the saving only happens when you drop below a tier boundary. Note that a suppressed profile stays suppressed even if they buy later, until they resubscribe or you lift it.
Free tool: Drop in a profile export: dead weight, likely bots and the tier you'd drop to
Runs in your browser; your list never leaves it. Tier prices are a snapshot you can edit.