We both have 'beep' cards.
In Cubao we are a short walk from the Transit trains of 2 lines.
In Marikina we have Katipunan and also Santolan stations.
Having said that have we only ever travelled on those trains once. Nightmare.
Yes, very cheap and convenient, but very very overcrowded.
It cost us P15 each from Cubao to Santolan.
The air-con UV Express is P20 each but does take a little longer

The regular jeepney costs P7 each. It's OK but if it looks like rain better to be dry than get wet especially if 'going' out rather than coming home.

The same trip using a 'Grab' taxi, which are large luxurious private taxis, comes in at a whopping P150