DMs are included with membership on every plan. Sending and receiving messages never costs Sparks.
Messaging with accepted connections is included. There is no daily message allowance: a long conversation never hits a wall. Fair-use protections prevent automated spam: sending very quickly in a burst may pause briefly, the same message cannot be blasted to many people, external links cannot be shared in messages, and bot-scale volume is stopped. None of these are product limits; they exist only to block spam and messaging campaigns.
Free Account members may start at most 3 new DM conversations per UTC day.
Receiving DMs is always included. You can read incoming messages anytime, in any number.