For public transport within Las Palmas, you need to get on the yellow buses, the Guaguas Municipales. Paying for a trip in cash costs €1,40. Paying with a buscard is a lot cheaper, only €0,85. Make sure to pay in coins or a small note (€10) since the busdriver usually doesn’t have a lot of change. The price is per ride; it doesn’t matter if you only stay on the bus for 1 stop or 15 stops.
The buscard you need is called Bono Guagua Sin Contacto and is available in blue or yellow. You can buy the buscard at small kiosks and the bigger bus stations (like Santa Catalina and San Telmo). Use Google Maps and search for estanco to find a kiosk near you. The buscard will cost you €10 and this includes 10 rides of €0,85.
When you use the bus, you only scan the card when you enter the bus. You can scan the card twice to pay for a friend or scan the card three times to pay for yourself and two friends, etc.
Charging your card is possible via their website or at the kiosks at the bus stations.