Hi Karl
Firstly you might want to edit your post to hide the database logon details (and change them on the database) otherwise you will find that some unscrupulous type will hack your database.
Secondly you don't need all those 'stripslashes' - that is for recieving user input not output from the database.
Thirdly to answer your question - you just need to use some sql like:
PHP Code:
$sql = 'select * from drinks where id = '.$drinkid;
make the call to the database - get the price of that drink and multiply by $drinkprice.