Maillegro 9090 Immersion Blender...I have lost all four blades. Does anyone know where I can buy them? Thanks.

match it up at any hardware store

Contact his Customer Service

https://wolfgangpuck.com/product/cookware/

..

http://www.braunhousehold.com/global/customer-support/instruction-manuals

Can it be that different for the other models listed at the above website?

Try pushing in the 2 small round buttons at the bottom of the base and pull up. That should do it.

Replacement parts for Wolfgang Puck Immersion Blenders are available here:

http://www.wpcookware.com/categories.asp?cat=26

If you do not see the model number for your product or parts are not shown, suggest you contact their Customer service at 1-800-275-8273 to determine if the required replacement part is available for your model. Alternatively try making an inquiry via their webform:

http://www.wpcookware.com/contact.asp

Replacement parts for Wolfgang Puck Immersion Blenders are available here:

http://www.wpcookware.com/categories.asp?cat=26

If you do not see the model number for your product or parts are not shown, suggest you contact their Customer service at 1-800-275-8273 to determine if the required replacement part is available for your model. Alternatively try making an inquiry via their webform:

http://www.wpcookware.com/contact.asp

If you have a model with the detachable blades. Otherwise, you'd need to purchase the blending rod from www.wpcookware.com.

I can sell you part of mine. I getting a new one to replace a part for mine. 

The B blade is the one to use - the B blade is the one with the "holes" in it.