After the 'Noddy' flexidisc my mum got me from sending tokens collected from Kelloggs Ricicles boxes, it was the single 'Jeepster', by T.REX.
The first album was 'Electric Warrior', also by T.REX.
These initial purchases with my own pocket money and earnings from a bread round proved a very difficult act to follow. In fact, despite my now massive collection, I don't think either have actually been bettered!