rollin9999

hey folks, new to the club, and new to bikes, so bare with me please im in france with my sr 125, i was taking a tight corner and leaning over quite a bit the chain came loose, and off the rear wheel cog (bad jargon, i know) so i put it back on, easily enough, but then it was really loose. anyways i continued along my merry way, bike still functioning just about. but sometimes the chain would come off, obviously coz its real loose.... so now i've had a friend tighten it, not sure how, i guess he took out some links??? apparently, the chain is completely wrecked, it badly needs oil and to be changed.... i know, i'm useless. so heres the quetions how much does a knew chain cost? roughly... with the oil, do i just pour it on like one would for a bicycle.... how long will this "completely wrecked" chain last.... will it do any other damage to the bike if i continue with it..... thanks a mill for any advice or tips, sorry about the rediculously trivial questions.... ps i wont be reparing it myself, due to lack of tools while travelling and complete ignorance!!!! rollin9999