Do you have a holding number to start with, you will need one to buy livestock. Then check the marts and see whats going, dont forget they need feeding over winter and costs maybe not worth fattening over winter as they will be young adults and not 'lambs'. We sometimes keep a couple of hogs on but they run with the ewes anyway and we have bred them not bought them. The price you will pay now is lamb slaughter price at the right age anything from now on is just added expense for older meat. I would ask around for someone with a couple of sheep spare to do the job if your reason to keep the sheep is only for land management and spend the money on some quality lamb now. You will still need a holding number to borrow sheep.