Enago Read
Among the cheapest literature tools with real quotas: three dollars a month buys fifty summaries and unlimited library size, which undercuts most rivals by an order of magnitude. It sits inside a recognised academic-services group rather than being an anonymous side project. The quotas are the thing to watch, since even the paid tiers meter summaries and insights.
Pros
- Premium at $3/month billed annually with unlimited library size
- Free tier is usable rather than a stub: 10 summaries and 10 insights per month
- Related-literature discovery over a very large source index
- Collaborator seats included on paid tiers
Cons
- Summaries and key insights stay metered even on paid plans (50 and 30 a month)
- No API and no offline or desktop client
- Advertised prices depend on a standing 50% introductory discount