Limiting the shopping cart to a dollar value

[textbook]

Hello,

 

I know that there is an option in the Admin area to change the maximum amount of products that can be added to the shopping cart, but I was wondering if anyone can help me out with something similar.

 

I was wondering if anyone knew how to limit the shopping cart to maximum dollar amount of $500.

 

I would really appreciate it if someone could help.

 

Thank you.

[textbook]

Hey, does anyone know of a way that I can acheive this effect?

 

I would appreciate any help.

 

Thanks.