Most course communities add pieces over the first year. Live sessions come first for many: Eventonomy gives event pages, recurring dates, RSVPs and attendee management, and it runs on the same login. Student work comes next: MediaVerse adds photo and video uploads with albums and privacy levels, and switches on direct messages. If you want to reward effort, WB Gamification adds points, badges, levels and leaderboards earned from real activity, and every part of it is free.
Paid upgrades come when a limit starts to hurt. Learnomy Pro adds drip content, assignments, grading, cohorts, subscription management and instructor payouts. BuddyNext Pro adds paid plans, gated spaces, broadcast email, push, analytics and auto and bulk moderation. Jetonomy Pro adds private messaging, polls, email digests, auto-moderation and analytics. Each sells separately, so you upgrade the one that solves today's problem.
The plugins page lists every piece with what is free and what is Pro. Because everything shares WordPress accounts, adding a piece never asks a student to register again.