Need new rear tire

you can some times find take off tire's/wheels on Ebay, but odds are all you need to do is look up brand and style/size of tire and just buy another, if all you want to do is just get 1 replacement tire for it?
you can also look on your local craigslist, or as far out as you'd go to get one, many folks sell used tires there too

pattern isn;'t as important as OD of the tire, as you need them to be all the same OD< so it keeps drive trail happy!