The short answer
No. HighLevel's pricing page says every plan, from Starter at $97 a month to Agency Pro at $497, includes unlimited contacts, so importing 50,000 names into a sub-account does not change the subscription. The cost that does follow list size is usage: each email, text segment and email verification is billed from your prepaid wallet, so a large list you message often costs more each month.
What the plans say about contacts
The pricing page FAQ answers this in one line: on all plans you get unlimited contacts and unlimited users. The plans differ on sub-accounts instead. Starter includes 3, while Unlimited and Agency Pro include as many as you need. So the real limit is how many separate businesses you can run, not how many people each one stores. A company importing ten years of customer history pays the same monthly price as one with 200 contacts. Enterprise pricing is set by HighLevel's sales team and is not published.
- Starter: $97 a month or $970 a year, 3 sub-accounts, unlimited contacts
- Unlimited: $297 a month or $2,970 a year, unlimited sub-accounts and contacts
- Agency Pro: $497 a month or $4,970 a year, unlimited sub-accounts and contacts
Where a bigger list does cost more
Storing contacts is free; reaching them is not. LC Email, HighLevel's built-in sending service, costs $0.675 per 1,000 emails, and HighLevel's email article says incoming and outgoing messages, including CC and BCC copies, are charged. Verifying addresses costs $2.50 per 1,000 checks. On the phone side, a US text is $0.00747 per segment plus a carrier fee of roughly $0.0035 to $0.0050 depending on the network. A weekly newsletter to 20,000 contacts is about 80,000 emails a month, or around $54 at the LC Email rate, before any texts.
Keeping usage in line with list size
Verify an old list before you import it: at $2.50 per 1,000, checking addresses once is cheaper than mailing dead ones every week. Use smart lists to send to segments rather than the whole database, and keep texts for people who opted in and expect them. If you run client accounts on Unlimited or Agency Pro, turn on rebilling so each sub-account pays for its own email and phone usage, at cost on Unlimited or with a markup on Agency Pro. A client with a huge list then carries its own messaging bill instead of your agency.
More answers in HighLevel questions. For costs, see GoHighLevel pricing or run the cost calculator.