Financial literacy can play an important role in supporting the livelihood of the poor. Sri Lanka, being a country that aims to become a knowledge economy, has started to integrate the use of technology in its primary education. This paper presents a case study from a Co-Design activity with primary school children in rural Sri Lanka to ideate designing of mobile applications to engage primary school students in financial literacy. Three workshops were conducted spanning over two months based on the bonded design method. Techniques involving bags of stuff, storyboarding and stickies were utilised to support idea generation. Two themes; shopping and transporting were prominent among the final designs. From the findings of this paper, we discuss the design inspirations of the study and the impact that scaffolding practices had on the outcomes of the study. Finally, we lay out some initial guidelines to follow when conducting co-design workshops with rural and resource constrained children in Sri Lanka.