It is also readily available at most pet stores. You will be using only small amounts so it is important to leave the bag in the freezer for freshness as well as to prohibit the growth of bacteria. Each morning take out small amounts that will be used during the current day. You will need to have something to use as a feeding tool. I like to use flat toothpicks for the first few days.
Some people like to use the small end of a banding tool as a pseudo spoon.
If you choose to use this type of tool it is very important that you wash and sterilize it after each use. After the first 5 or so days I switch over to mini disposable pipettes. These are meant to be one use only. Yes, it is more expensive but for me it is much more important not to have to deal with any sort of possible bacteria contamination. Have pedialyte on hand.