As was pointed out, buying street phones can be a risky business. A quick search on www.classifieds.co.zw reaveled the cheapest used s3 from an actual shop being listed for $170. Cheapest new s3 $210.
http://www.classifieds.co.zw/index.php?a=19&c=23755&b[search_text]=galaxy%20s3&b[search_by_field]=title_only&b[subcategories_also]=1&b[search_titles]=1&b[search_descriptions]=0&order=1
http://www.classifieds.co.zw/index.php?a=19&c=23755&b[search_text]=galaxy%20s3&b[search_by_field]=title_only&b[subcategories_also]=1&b[search_titles]=1&b[search_descriptions]=0&order=1