I support the Banff Protocol and will no longer submit papers to overpriced journals. I won't referee for them either.  Why waste resources when plenty of good journals publish for much less?  An enormous list of journals, sorted by the price per page, can be found here, but the following journals regularly publish papers in operator algebras -- at half the cost (or less) of Inventiones.  

• Comm. Math. Phys. (66 cents/page)
• Acta Math. (65 cents/page) 
• Bull. AMS (64 cents/page)
• Proc. LMS (63 cents/page)
• Journal LMS (58 cents/page)
• Canad. Math. Bull. (53 cents/page) 
• Ergod. Thy. Dyn. Sys. (52 cents/page) 
• Duke Math. J. (51 cents/page) 
• J. Algebra (51 cents/page) 
• J. Funct. Anal. (50 cents/page) 
• Canad. J. Math. (50 cents/page) 
• Bull. LMS (42 cents/page) 
• Math. Scand. (41 cents/page) 
• Adv. Math. (41 cents/page) 
• Rocky Mount. J. Math. (37 cents/page) 
• Math. Res. Lett. (36 cents/page) 
• Transactions AMS (28 cents/page) 
• Proc. AMS (26 cents/page) 
• J. Operator Thy. (24 cents/page) 
• Journal AMS (24 cents/page) 
• Amer. J. Math. (19 cents/page) 
• Pacific J. Math. (18 cents/page) 
• Doc. Math. (16 cents/page) 
• New York J. Math. (16 cents/page) 
• Illinois J. Math. (14 cents/page) 
• Annals Math. (13 cents/page) 
• Houston J. Math. (10 cents/page) 
• Indiana Univ. Math. J. (10 cents/page) 

If there is a journal that you'd like to see added to the list, please let me know.