The YS50's will work just fine off the headphone output. They have a volume control. I don't believe you'll find anything even close for that price.
Incidentally, I don't recommend it, but I've dropped mine twice from a height of about three feet. Other that some skin marks and scratchs, no damage. I bought a second set for backup or future use.
I'm using them as my sole speakers for everything up to 50 or 60 people and have got nothing but good reviews.
DonM