As many Frankfurt fairgoers know, for the most popular fairs most hotels more or less double their usual rates--and in many cases travel agencies lock out blocks of rooms and mark them up to an even more exhorbitant rate. So my experience is colored by this reality of price-gouging no matter the quality of the hotel. However, the hotels close by the fairgrounds such as the Maritim and Marriott, and even the cheapie neighborhood hotels, are the most susceptible to price inflation for heavily attended fairs.