Changing Money/Bringing Money Back to the USA (Santiago de Chile)

I'll be going back to the States for a visit next month and want to bring money back with me. I'm trying to figure out the best way to convert it to dollars.

Is it best to go to a casa de cambio here, or is it better to convert it back home? I don't have a problem carrying the money and don't want to pay a percentage to Western Union or Money Gram,

I got a great exchange rate a while ago (when it was at Protected content per dollar), but now it seems like it's going to be over 500. :-(

Thanks for the advice!