[bartp5]

It doesn't really matter where it is. The executable is self contained,i.e., if you call it with its full path it will work from anywhere. Usually I put the stuff I compile in /usr/local/bin/.

Edit: Note that the stripped down busybox wget is already in your boox and in your path so just typing wget will get you the stripped down version. Best put this wget somewhere outside your path and point to it by typing the whole path.