With some Economy Fares the maximum combined Linear Length of any two pieces of checked baggage is 273cm/107in but no one piece may exceed a Linear Length of 158cm/62in - in which case the other piece may not exceed a Linear Length of 115cm/45in.
So for a 30 gram serving of protein it would cost about $1 per day. From these two samples of protein powder I found that an acceptable price range for 30 grams of protein from protein powder is between $1 and $1.50 (assuming close to equivalent protein powder quality).
The Daily Value (%DV) for protein is set at 50 grams per day, this number is meant to help compare foods and is a general number that works for most people. Foods high in protein per calorie include lean chicken, lean pork, fish, lean beef, tofu, beans, lentils, low-fat yogurt, milk, cheese, seeds, nuts, and eggs. Below is a list of common foods high in protein by common serving size, for more information, see the sections on protein dense foods, other protein-rich foods, and protein isolates.