I get asked this question quite a bit. Here is the basic explanation of the differences:
- Shopping cart
Allow customers to choose one or more items for a single checkout. - Automatic billing
Sign customers up for a billing agreement that allows you to charge them a variable amount – up to a mutually agreed upon maximum – each billing cycle. For example, utility bills. - Buy Now
Let customers click once and quickly purchase one item at a time. - Donations
Let customers choose a fixed or variable donation amount. - Gift certificates
Sell gift certificates in predetermined amounts or allow customers to choose their own amount. - Installment Plan
Let customers pay for items using flexible multiple payments. - Subscriptions
Offer subscriptions or other recurring payments for items like magazine subscriptions or club memberships.