removing price and buy button - gridmarket + marketpress

I'm using gridmarket and marketpress with the "Product Listings Only" option set in the marketpress options.
I've hacked the header.php to disable the cart, and now I just need to remove the price and buy buttons from both the main product page as well as the individual products. I have found several instances of show_price and show_button in the code, but commenting them out causes errors.
Could someone please point me in the right direction? Thanks in advance.