Thanks for everyones advice, now I REALLY don't know what to do !
Both sides have + / -'s problem with buying a tiller, can't really take it back if you are un happy ! I don't expect my roots will be any larger than 2". And who knows about rocks, most are under the dirt so you won't know till you till.
With small roots... does the tiller just bury them or spit them out ????