Here we go:

Name	Area	Adress	Phone(germany)	Single Room	Dbl Room
Hotel Atlas	Bahnhofsviertel	Zimmerweg 1	069/723946	68DM per night	98DM per night
Hotel Bacher*	Westend	Mendelssohnstr.92	069/747992	30DM per night	60DM per night
Hotel Bruns	Westend	Mendelssohnstr.42	069/748896	60DM per night	79DM per night
Hotel Gölz	Westend	Beethovenstr.44	069/746735	65DM per night	135DM per night
Pension Stella²	Nordend	Frauensteinstr.8	069/554026	65DM per night	120DM per night
Haus der Jugend³	Sachsenhausen	Deutschherrnufer 12	069/619058	21DM/34DM

* 3DM for a shower :P

² prices including breakfast

³ you need a DJH (DeutscheJugendHerbergen I guess..youth hotels) members card! If you have one you pay 21DM if you are max.27years old, over 27 your pay 34DM! That should include a meal or sth I aint sure, if you have a DJH members card I am sure you know better about this stuff than I do!

OK! That's about what I found out. I don't know any of these hotels, but they are advertised on the official Frankfurt Main Homepage, so you can expect that they are not selling their rooms to whores or similar stuff. It's ok hotels from the description on the page, should be fine for a night or two! Mind that you might be able to save some money if you share a room with someone....