Below is a concise, practical guide to payment‑gateway / payment‑processing options for small U.S. businesses (online + in‑person). I list each provider’s core role, typical fees/features, strengths, weaknesses, and which business types they fit best — plus quick tips for picking and lowering costs.

Big/commonly used options (with typical US rates and features)

• Stripe — all‑in‑one payments platform for online & in‑person, strong developer APIs.

  • Typical fees: 2.9% + $0.30 per domestic online card transaction; lower in‑person rates (2.7% + $0.05); extra for international/manually‑entered cards. Stripe has many add‑on products (billing, Connect, Radar fraud tools). (Stripe.com)
  • Strengths: best for online sellers needing customization, subscriptions, marketplaces, or global payment methods; excellent docs and integrations.
  • Weaknesses: developer work often required to customize; chargeback fee (dispute) applies.
  • Best for: SaaS/subscription, eCommerce stores, marketplaces, companies with developers.

• Square (Block) — POS + payments focused on local retail/food/appointments.

  • Typical fees: in‑person contactless/chip/swipe ~2.6% + $0.15; online 2.9% + $0.30; keyed/manual and invoice rates are higher. No monthly fee for basic POS. Hardware (readers/registers) available. (squareup.com)
  • Strengths: plug‑and‑play for brick‑and‑mortar, built‑in POS, fast deposits, simple pricing, hardware ecosystem.
  • Weaknesses: less flexible for complex online flows or custom marketplaces; higher keyed‑in fees.
  • Best for: cafés, pop‑ups, retail stores, service businesses needing simple POS.

• PayPal / Braintree — recognizable brand, easy checkout options, Braintree for developer integrations.

  • Typical fees: PayPal business card processing ~2.89% + $0.29 (varies by product) and PayPal/Venmo consumer payments often have different rates (e.g., PayPal/Venmo checkout ~3.49% + $0.49); Braintree standard card rate often shown ~2.89% + $0.29; ACH pricing and other services vary. (There are product/plan differences and optional monthly fees for advanced products.) (PayPal.com)
  • Strengths: very familiar to customers, easy one‑click checkout options, Venmo/PayPal presence can boost conversions, Braintree is developer friendly.
  • Weaknesses: fees can be higher for some flows; account holds/customer disputes can be more common for higher‑risk merchants.
  • Best for: sellers who want easy buyer trust/recognition, marketplaces wanting multiple wallet options, those who want a mix of no‑code and developer integrations.

• Authorize.Net — legacy payment gateway that can be used with merchant accounts or as an all‑in‑one.

  • Typical model: gateway service (monthly gateway fee) + processing via a merchant account; many small businesses sign up through resellers or the all‑in‑one plan. Alternatives (Stripe/Square) bundle gateway + processing with no monthly fee for many small users. (See consumer reviews/roundups for comparisons.) (nerdwallet.com)
  • Strengths: long track record; useful when you already have a merchant account or need specific gateway features.
  • Weaknesses: monthly gateway fees and more configuration; not as modern/easy as Stripe/Square for new online businesses.
  • Best for: merchants who prefer traditional merchant account setups or who have an existing processor they want to keep.

Other useful options & notes

• Shopify Payments — best if you run a Shopify store (integrated payments, simpler setup). If you use Shopify but disable Shopify Payments you may pay extra fees. Good when you want an all‑in‑one store + payments solution.
• Payment facilitators & marketplaces (Stripe Connect, Braintree Marketplace) — required if you run a marketplace and need to split payouts.
• ACH / bank debits (Stripe ACH, PayPal ACH) — cheaper per‑transaction for high‑ticket B2B payments (often 0.5–0.8% with caps), but longer settlement and possible returns; good for invoices and subscriptions.
• Payment gateways vs merchant accounts: gateways (Stripe, Square) bundle processing and gateway. Traditional merchant accounts + gateway (Authorize.Net + separate processor) can be cheaper at high volumes but are more complex.

How to choose — quick decision framework

1. If you’re primarily in‑person (retail/restaurant): choose Square (easy POS + hardware) or a Clover/Toast (restaurant) solution. (squareup.com)
2. If you’re primarily online and need custom checkout, subscriptions, marketplaces or global payment methods: choose Stripe or Braintree. Stripe is simpler to start and has a huge ecosystem; Braintree is good if you want PayPal/Venmo tightly integrated. (Stripe.com)
3. If you want maximum buyer recognition/express checkout: offer PayPal/Venmo as an option (can increase conversions). (PayPal.com)
4. If you process high volume and want lower rates: ask for interchange‑plus or custom pricing from Stripe/Square/PayPal or go with a merchant account + gateway (Authorize.Net) and negotiate rates. (nerdwallet.com)

Ways to lower costs

• Reduce keyed‑in transactions (keyed transactions cost more).
• Encourage card‑present payments (lower in‑person rates).
• Offer ACH or invoice payments for large B2B transactions.
• Negotiate interchange‑plus pricing when you reach volume thresholds.
• Use one provider for both POS and online (some providers give discounts for unified volume).
• Avoid long settlement delays by picking providers with fast payouts or opt for instant transfer features (small fee).

Practical implementation checklist

• Decide which payment types you must accept (cards, wallets, ACH, buy‑now‑pay‑later).
• Confirm monthly fees, per‑transaction rates, chargeback fees, and hardware costs.
• Check integration needs (plug‑and‑play vs developer API).
• Review payout timing (1–2 business days vs instant with fees).
• Confirm fraud tools, PCI compliance responsibilities, and customer support options.
• Test checkout flow on mobile — many losses occur on mobile checkout.

Final recommendation (short)

• If you want the simplest path for in‑person retail: Square. (squareup.com)
• If you want most flexible, developer‑friendly online payments (subscriptions, marketplace, global): Stripe. (Stripe.com)
• If you need PayPal/Venmo checkout recognition or a hybrid approach: add PayPal/Braintree as an option. (PayPal.com)

If you’d like, I can:

• Compare 2–3 specific providers side‑by‑side for your exact business model (annual volume, average ticket size, online vs in‑person).
• Or list simple plug‑and‑play setups (links to signup docs, recommended hardware) for in‑person stores vs online shops.

(Notes & sources: Stripe pricing page; Square pricing/support pages; PayPal Business and PayPal Braintree pricing pages; Authorize.Net reviews/roundups used for comparison.) (Stripe.com)