I was travelling around the internet, and I found few sellers of amd graphic cards. but the prices are strongly lower than in other services. can u help me with the info? is it normal situation, or nobody should trust sellers like these?
Not a simple answer to that.
New cards from AIB partners(asus, xfx, sapphire, (several ? others)) usually have a 2-3 year warranty, OEM partners( hp,dell, etc...) may be less.
Then there are 2nd hand/refurbished/repurposed/questionable rebadging products.
Up to you to fully research any seemingly cheap priced product/seller. There have been fake cards sold before.