The past decade has seen a growth in demand for human eggs for stem cell related research and, more recently, for mitochondrial research. That demand has been accompanied by global debates over whether women should be encouraged, by offers of payments, in cash or kind, to provide eggs. Few of these debates have been informed by empirical evidence, let alone by the views of women themselves. This article addresses that gap in knowledge by presenting findings from a UK investigation, conducted 2008-2011, which is the first systematic study of women volunteering to provide eggs under such circumstances. This article focuses on the views and experiences of 25 IVF patients who volunteered for the Newcastle 'egg sharing for research' scheme (NESR), in exchange for reduced IVF fees. This was an interview based study, designed to gain understandings of volunteers' perspectives and reasoning. The interviews show that volunteers approached the scheme as a way of accessing more treatment in pursuit of their goal of having a baby, against a landscape of inadequate state provision of treatment and expensive private treatment. The process of deciding to volunteer raised a wide range of uncertainties about the consequent gains and losses, for women already in the uncertain world of the 'IVF rollercoaster'. However, interviewees preferred to have the option of the NESR, than not, and they juggled the numerous uncertainties with skill and resilience. The article is as revealing of the ongoing challenges of the UK IVF bio-economy as it is of egg provision. This article adds to the growing body of knowledge of the contributions of tissue providers to the global bio-economy. It also contributes to several areas of wider sociological interest, including debates on the social management of 'uncertainty' and discussions at the interface of sociology and ethics.