The first and most important piece of advice is to choose proven online stores when shopping online, ie e-shops that are well-established, well-known and ideally large enough. If they are used by many other customers, the shop or e-shop is safe.
Make sure the eshop has it properly filled in contacts in the header or footer of the page. The contact should consist of: address, ID number (or VAT number - you can verify the entry in the Commercial Register of the Slovak Republic) and information about the company, or who is behind it. Only well-known and reliable stores can be found on the site zlavove-kody.sk and for Czech shops it can be http://www.slevovy-kod.cz/. The site displays discount codes that will also save you money.
Next, the e-shop should include options for transport of goods, payments, business conditions, information on personal data protection, complaint conditions and instructions for returning goods. We have already mentioned pages where you can find discounts for well-known e-shops, if you want to check it somewhere else, or find other coupons and discount codes, you can also search for zlavuj.skwhere there are thousands of discounts.
If the e-shop is secure and trustworthy, it will be secured via the HTTPS communication protocol. You can easily verify it - the lock is locked in the line with the URL of the page and after clicking it will be displayed security certificate.