For simple and easy auctions payments or manual price entries:

1) in the main commerce.cgi file:

under sub add_to_the_cart, find this line

if ($item =~ /^option/i){

and add this directly BELOW it:

	#Manual price entry hack by Chris Costa
	if ($item =~ /^option\|price/i){
	$form_data{$item} =~ s/\$//ig;
	$form_data{$item} = &format_price("$form_data{$item}");
	$form_data{$item} = "Price|"."$form_data{$item}";
	}	
	# end manual price hack

2) Now just name a text box in an option file like this:

<input type="text" name="option|price|%%PRODUCT_ID%%" size="6" maxlength="10">

That's it!  Now users can manually enter a price and it will show up as the price of the item in the cart.

I would suggest also adding to your option file some code to replace the quantity box with a hidden field set to "1".

Best of luck,

Chris Costa

More great commerce.cgi hacks found at:
http://www.wildaboutbeads.com/hosting/scripts