Grandfathered ($195) class 5 sims are rare, Linden Lab only sold them in November and December 2006. Back then, they announced a tier increase in conjunction with the introduction of class 5, along with a blowout sale of all remaining class 4s in stock; demand was so great that after the class 4s were sold out, remaining orders were filled with grandfathered class 5s instead.
If you have one and are willing to sell, please let me know. Would offer $1800 if monthly billing anniversary was tomorrow, or $2000 if monthly billing anniversary was yesterday.
PS, if you have a grandfathered sim and aren't sure if it's class 4 or 5, log in to http://secondlife.com/ --> Land Portal --> Estate Management --> [name of your estate] and check "Server Class" column