Three posts.
One is Mailchimp Standard: $20 a month to start, for up to 500 contacts, with a higher price once the list grows. One is HubSpot Marketing Hub: $20 a month per core seat to start, $890 a month for Professional, and $3,600 a month for Enterprise. One is the difference between those two purchases. An email plan and a marketing seat can both cost $20 and still be different products.
The software page has the other categories, including the ones that do not have a single price worth quoting out of context.