almost non existent.... if your not getting a HD cap card dont expect shit
Easycap-$10-$30 (add 15-20 to it for s-video cable and splitter if you dont have it)
cheapest, and it shows, but it works with mac aight
Kaiser Baas-$50: http://www.kaiserbaas.com/gaming/series-8-game-recorder
60fps not bad, seems aight
Dazzle-$80: popular cheapy
i got the easy cap, on mac (now pvr but did have), with the right settings and a s-video cable (from xbox to svideo) its...... something (gotta make sure you get the right version DC not DC+)
save for a avermedia or pvr.... but then its kind of hard to justify paying 100 bucks to record a video game, idk, i did it anyways