As somebody who has owned the PS2, xbox 1 (original xbox), 3 xbox 360's and now deciding between the xbox one or PS4, let me venture a guess.
1. original Xbox 360, - ~$100-200
2. rgb/scart video connector, - ~1
3. Two hard disks, one 20GB and one 250GB - ~$50
4. Three wireless controllers - ~$20
5. five rechargeable battery packs for the controllers, - ~$50
6. xbox live vision camera, - ~$10
7. two headsets, -$5
8. ethernet cable and -~$1
9. forty-nine games ~$300-$1000
In total between $500-$1500. The games are the the expensive and volatile bit. Top rated games like Bioshock etc, even used will fetch at least $20, the cheaper crappy ones can go for even $3. Looks like solid bundle and since most of the games are top rated, I suspect the bids will get to at least $500.
My 2c.
Hmm... also noticed that he only ships to the UK.