Solution:
1) Sudo PATH and user PATH differ. That's why 'sudo php -v' doesn't work.
User's path:
echo $PATH
/home/alan/home/alan/netbeans-8.0/bin/netbeans/usr/lib/lightdm/lightdm:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin:/usr/games:/opt/lampp/bin
A proper way to echo sudo's path:
sudo /usr/bin/printenv PATH
/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin
2) I've installed PHP from repositories. I can now call 'sudo php'.
sudo apt-get install php5-cli
Thanks Matt and guys from Ubuntu forums(spjackson & SeijiSensei)!