The Prophet ﷺ taught poor emigrants, who could not give charity the way the wealthy did, a set remembrance to say after every prayer: SubhanAllah 33 times, Alhamdulillah 33 times, and Allahu Akbar 34 times — by which they could match the reward of the wealthy's charity. Simple, constant remembrance of Allah is among the easiest and most rewarding acts of worship.
Informational, not a personal fatwa. Consult a qualified scholar for rulings on your situation.