Amd Athlon x4 760k 3.8Ghz
Sapphire Radeon r7 260x
MSI a78m-e35
Corsar cx430
16gb Ballistix Sports DDR3 Ram
1TB Western Digital Caviar Blue
500gb Seagate Hard Drive
Corsair Spec 01

Somebody offered me this computer for 350 euros. Is that a good deal?

not horrible, could get ripped off bigger. Not a bad set up if you like or dont mind AMD products.

coud get ripped off bigger sounds kind of like it is not the best deal

is it worth the money though? To be honest I dont mind AMD because I simply have no idea about the difference of AMD, Intel and NVidia

its worth $300 if that is what you are asking. but doesnt seem like a great set up. just buy it use it and be done with it. all of this will all be trash in the next couple of years.

but it is not necessarily a good deal then right? And would you recommend to buy this one second hand, or to invest some more cash and get a better new pc?

What he means is you get what you pay for. Get something cheap, like this and it'll be trash next year or spend the money on something nice that will last. Honestly it all gets dated fairly quickly so honestly I'd just buy it until you are more sure, just my personal opinion considering you don't sound much like you know what you want :P happy holidays.