Online shopping can be very secure, but that does not mean that there are no risks involved. However, if you are a little careful you will not face any particular problems.
In purchases from Greek stores, prefer cash on delivery. It costs a little more but will save you from voices on the phones and capital letters in emails. Many times stores have no stock and hold your money "hostage" until they bring the product back. No one has too much money to keep in their pocket. You got something, you want it at the time you were promised, not later.
What to look out for: 

1. Make sure you know what the business is and how you can approach it
Is the name and normal (postal) address of the company on the website? Is there a way to get in touch with the business via email or phone? Are you already familiar with this business? If not, have you checked it through consumer organizations, or from other possible sources of consumer information? Does the company belong to one of the programs that require to follow good standards of behavior and reliability (such as Web Trader)?

2. Make sure you understand what you are buying
Can you figure out exactly what you are buying based on the website description? Are photos, product contents, measuring instruments or other information you may need provided? Do you understand how the product or service works?

3. Make sure you understand what you are going to pay
Are all expenses listed, including price, shipping, taxes, or other charges to be paid? Do you understand what is included in the price and what may incur additional costs? If the expenses are in foreign currency, does the website provide you with a way to calculate them in your own currency? If not, have you checked the latest exchange rate of the drachma with the foreign currency?

4. Make sure you understand how to pay
What options do you have for how you will pay? Have you checked through consumer organizations to find out if you have special legal rights if you pay in a certain way? For example, in some countries you can claim credit card refunds if you do not pick up the product or it was presented incorrectly. Does your card issuer have an optional measure or program that gives you extra protection when you use it to shop online?

5. Make sure there is a clear commitment on when you will get it
Does the website tell you when the items will be shipped or when the services you ordered will be provided? Tells you if there are any geographical or other restrictions on shipping and receiving? What options do you have for how the items will be shipped and who pays the cost? What does the website say about shipping security?.

6. Make sure you know the options you have if you do not want to
Can you cancel the order before you finish while you're logged in? Once the order has been given, can you cancel it? Can you return the purchase later, and if so, are there any time limits or other restrictions? Is there a cost for you if you cancel the order or return the product? Are you getting your money back or are you crediting your account for future purchases?

7. Make sure it is guaranteed
Are there any guarantees for the products or services? What do they include? What are the limits? How long do they last? Can you easily exercise your rights during the warranty?

8.Make sure you have after-sales support
How can you access the customer service department? Is there an easy way to make repairs or get the support you may need later?

9. Make sure you have evidence of the company's promises
How does the company confirm your order? Can you print the information for the transfer of the order in case you need it later? Does the information include the order number or customer that characterizes your purchase?

10. Make sure there is a way to protest
Does the website tell you how to complain? Explain the handling of complaints? Does the website tell you that you are bound by the laws of another country? Does the company provide an easy way for you to resolve disputes without relinquishing your country's legal rights?

11. Make sure your information is secure
Does the website tell you how your financial and other personal information is protected during transfer and storage, if any, after the transfer of the order?

12. Make sure your privacy is protected
Does the website allow you to search anonymously? If he collects information about you, does he tell you what information he collects and how he uses it? Does it ask you to provide unnecessary personal information when you want to make a purchase? How well do you control the collection, use and accuracy of your personal information? If you do not want to get direct buying advice from this company or from others with whom you can share your information, is it easy to make this choice?