Your grandmother is old, and her health is the most important. It's best to send some health products, such as massage cushion, heated footbath, tea pillow, etc. Of course, you can also send flowers to make the old people feel comfortable. In addition, considering that you may still be a student, if the economy is really limited, send blessings, and the old people can feel your heart and your filial piety. Happy birthday to your grandmother.