G298100 has been posted as good for Europe in general, although I do not know where this particular AWD number is sourced from. (Gevoha has been mentioned previously, as some sort of computer company, but actually that name is for a Jewish Yeshiva in New Jersey, so this attribution is very dubious!)

K851000 is the AWD number for Hhonors, and it has been mentioned that it works well in Italy.

A153700 and D086533 have been mentioned as being good AWD numbers both specifically for Italy, and generally for Europe, although I do not know where these particular AWD numbers are sourced from. (They have been mentioned as both being for the same company, the first one for employees of that company [I saw one mention that this is the US Avis employee number, so beware!], and the second for customers of that company, but the company name is not certain.)

B149870 is supposed to be good in Europe generally, but again, the company affliliation is unknown.

L358190 is the number for the BMW Car Club of America, and should work worldwide. Note - this is for a club, not for a company, so the RA will never be able to ask you for your company ID!

At least one of those should give you a 30% discount, and one or two on the list might be as high as 50%. However, some of these will work in some European Countries on certain dates, but might not work in other European Countries, or on other dates. YMMV Let us know what works, okay?