I'd really like a copy of GoTY Morrowind for PC

but how do i know that it will include everything and wont be damaged or they wont send me a box of paper clips

Contact the seller and ask for more informations/pics of the product. Also, look at what price the game is offered (goty for 5$ would be suspicious) and the seller reputation/buyers feedback. But most of all, stay cautious.

I used to do a fair amount of eBaying, mostly for old movies that I wanted to fill out my DVD collection. In general, I have found that buying used digital media on the internet is a risky business, even on eBay. I received a number of things that were not of the quality advertised, and a few that would not play at all.

That said, I also found a few sellers that always delivered what they said they would deliver. It took a little trial and error, but looking at the seller's reputation, and comments from their buyers, can help a lot! If you have someone who has made hundreds of people happy, you're probably in good shape. Use your best judgement.

Hope that helps!