"Free things, offers, and resources" matching MCP servers:

Discover audio and LLM services, compare seven voices, and check prices for free. Generate speech, transcribe audio and request LLM text with optional capped USDC payments on Base; voice-cloning requirements are also available.

Credit and payments for AI agent developers — over MCP. No crypto required

Checks live x402 routes across Base, Solana, and Algorand before agents spend. $0.003 USDC settles only for a valid live eligible route; normal typed misses are not settled. Free preview and validate tools. Seller payment is separate; the agent keeps its wallet. Optional signed route-binding receipts support buyer-side checks.

The first commercial implementation of HTTP 402 Payment Required for creator content. AI agents discover music, video, and text catalogs as pre-indexed Pockets (list_pockets, search_pockets — free, no key) and pull licensed content per-use through a 402 paywall. Tiered per-pull pricing by content type; 85% of every pull pays the rights holder instantly, with attribution and an audit trail.

MCP server that gates API calls to AI agents using proof-of-work (free) or Lightning payment (3 sats), providing challenge, verify, and status tools for per-call authentication without accounts.

A template for building MCP servers with a built-in paywall gate that offers free local execution and premium server-side execution via Stripe and x402 payment lanes.

Enables AI assistants to build PayRetailers cross-border payment integrations accurately by providing official documentation, endpoint specs, country-specific payload validation, webhook guidance, and integration prompts as MCP resources, tools, and prompts.

MCP server providing Polymarket weather-market bucket-transition signals for AI agents, with free city/signal inspection tools and paid signal bundles via USDC on Base using x402.

Create free, no-signup invoices from your AI assistant — the create_invoice tool returns a link that opens blankinvoicemaker.com pre-filled, ready to download as a watermark-free PDF.

MCP server for real FDM 3D-printing slicing, quoting, and design-for-manufacturability analysis via the FabTally API, supporting 12 printer profiles and 12 materials. Includes free discovery/printability tools and paid slice/quote/orientation tools settled via x402 (USDC on Base).

MCP server exposing a fictional payment domain as tools, resources, and prompts, enabling reasoning over transactions, payment hubs, services, and system health.

Generate crypto QR codes (BTC, ETH, SOL, USDC, USDT, EURC) and manage payment sessions from Claude Desktop or any MCP client. Non-custodial, free.

Provides AI agents with SSRF-protected URL intelligence and 32 paid REST/MCP tools, plus a free catalog search, with payments in USDC on Base Mainnet.

Payment firewall for AI agents: a signed, independently verifiable verdict on every money-moving action. Blocks wrong/lookalike payee, over-cap, and duplicate-invoice (BEC) fraud before money moves — anyone can verify a verdict against the public JWKS. Free, local-first, non-custodial.

Quote, book, and track real LTL, FTL, cargo van, and box-truck freight through the Warp network - 20 tools, in-chat login, Stripe-charged bookings, and real carrier dispatch. Quoting is keyless; booking needs a free Warp account with a card on file.

AI-powered invoice automation. Create PDF invoices, predict late payment risk 0-100, auto-send reminders, reconcile Stripe/PayPal payments, track cash flow. 10 MCP tools, 4 resources.

Enables AI assistants to query and manage ThriveCart data across multiple accounts, including products, offers, transactions, revenue, customers, subscriptions, and affiliates, while keeping accounts separate.

Discover and pay for APIs and MCP tools per call over Bitcoin Lightning (L402): search the bolthub marketplace, preview prices, and pay from your own wallet (LND, NWC, LNbits) with hard budgets, prepaid credit, scoped sub-agent delegation, and verifiable receipts. Non-custodial and works without a wallet for search and free tools.

MCP server for Sean-Claude Van Damme's General Store, enabling AI agents to browse and purchase digital goods and services using USDC payments over the x402 protocol.

Identity infrastructure for the agent economy. Mint an agent ~handle in two free calls with no human account, then verify anyone and read inferred traits under the consent the person set in advance.