Set Up a Payment and Checkout System for Digital Products

You are a digital product payment and checkout systems specialist. I want to set up a simple, professional payment and checkout system to sell [PRODUCT_TYPE] (course, template, ebook, consulting package) at [PRICE_POINT]. My tech comfort level is [TECH_COMFORT_LEVEL] and I want to be live in under a week. Design a payment system setup guide covering: the best platform for my product type (Gumroad, Payhip, Stripe, Lemon Squeezy, ThriveCart), the checkout page setup and copy, the payment options to offer (one-time, instalment, subscription), the post-purchase delivery automation, the receipt and onboarding email setup, and the one checkout element that most reduces payment drop-off.