PayPal

PayPal is the most known online payment processors and online 'wallet' where you can store funds in multiple currencies. 
It supports online payments and money transfers and also serves as an electronic alternative to traditional paper methods like checks and money orders.
It is known not only to sellers but also has wide acceptance from the buyers. Because of this popularity, many physical stores accept Paypal payments, so that clients can use their PayPal balance.

PayPal is owned by eBay.

PayPal offers 3 Account Types which all allow you to send and receive payments.

• PayPal Personal: With a Personal account, you can make payments to almost anyone with an email address. You can make and receive some types of payments without incurring fees, and pay low fees for others. For more information, see the fees section of the PayPal User Agreement.
  PayPal personal accounts are ideal if you want to shop online and send or receive personal payments to friends and family.
• PayPal Premier: PayPal premier accounts are for people who may be casual sellers but are not registered as official businesses.
• PayPal Business: Recommended for merchants who operate under a company/group name.
  Business Accounts allow you to display your Business Name or Business Logo Graphic on the PayPal Checkout Screens.
  It offers additional features such as allowing up to 200 employees limited access to your account (Multi-User Access) and customer service email alias for customer issues to be routed for faster follow-ups.
  If your business is setup, registered, etc., then go with a Business Account.

Seller name: In PayPal's buy page the customer sees the name of the seller and the name of the product or service they are buying.

• Selling by an email address: If you have a PayPal personal account you can sell by an email address instead of your personal name. This provides a minimum of anonymity and protection of your personal data.
• Selling by a business name (not by your personal name) can be done but this would need to be the name registered with your bank, i.e. the name verification is done via the bank's account name.

Issued debit card: PayPal Cash Plus account is required to get the Mastercard debit card. With the debit card you can use your account's balance like a normal bank account and make purchases from where ever the MasterCard is accepted. For example, you can use your account's funds to pay for your google adwords advertising. Google Adwords does not accept PayPal as a payment method and the debit card removes this barrier.
Note: this is probably a discontinued feature. Information about the PayPal debit card leads to pages that no longer exist.

Additional fees: In addition to PayPal's per-transaction fee, you will also incur the following fees:

• $30 per month if you want to design and host your own checkout pages.
• 1% cross-border surcharge if you want to accept payments from another country.
• 3.5% transaction fee when your customers pay with American Express.
• $0.30 per uncaptured authorization.
• A fixed fee portion of the original transaction fee when you issue a refund ($0.30 for domestic payments).