Your CSV file doesn't appear to be formatted correctly:
"book,50"
Should probably be:
"book",50
- or -
"book","50"
Otherwise, "book,50" will get interpretted as 1 field, which is definitely allowed, but doesn't appear to represent what you want to do.
Secondly, take a look at [man]fgetcsv[/man]. You'll need to read in the entire file, or all of the file up until the record you want, and then retrieve the necessary field you're looking for (it'll be a numerical array starting at 0, so in this case, you'd want array element 1 where array element 0 == book).
Keep in mind, CSV files DO NOT scale at all. Meaning, the larger the CSV file, the worse the performance will be. With small CSV files, you'll be ok.
