The ZTE MF60 was recently sold for € 53 in Germany (
ZTE MF60 Mobile Hotspot ab 53? *UPDATE* » Hotspot, Empfang, Mobile, Stunden, MF60, MiFi » myDealZ.de).
RTL also sell a quite cheap Mifi called "Vodafone R201", which in fact is a derivate from the Huawei E5 series and comes unlocked for € 65 including a "RTL Surfstick" SIM with € 10 of credit:
RTL Surfstick - mobiles Internet im Stick
But the MF60 is better as it suppports higher HSPA-bandwidths, more Wifi clients (max. 8 instead of 5) and it has an antenna connector.