I know there is an antiques consignment shop in Arlington, on Mass Ave, that sells (among other things) antique tea sets - the Lena Nargozian Gallery. (There may be someplace else closer to you; I just happen to have stopped by that store lately and noticed they were selling tea cups in price range you described. I don't know the owners or whether they're nice.) They (or a similar shop) could almost certainly give you an appraisal and would likely sell the set for you, which seems possibly easier than having to transform yourself briefly into a tea set selling expert.