Manufacturers are now churning out 4,000 of the micro-computers daily to meet demand, but customers who place their orders now are unlikely to receive theirs until September.
"Orders can now be placed for unlimited quantities of Raspberry Pi board and accessories without the need to register or to receive an invitation to order," said a spokesperson for RS Electronics.
"We're currently forecasting that these orders will start reaching customers by the end of September.
"Customers will be provided with a forecast future delivery date when placing their order, and these orders will be fulfilled after all orders placed before 16 July have been shipped."
Raspberry Pi is a credit card-sized machine that aims to generate interest in programming among school children. The budget device, which runs the Linux OS, comes uncased without keyboard or monitor.
The computer is available to purchase now, priced at £25.
Watch the Raspberry Pi running a ZX Spectrum emulator below: