That was long after MSP430 were widely used, that pricing was part of the launch of the "value line" G-series (And it's associated MSP430 LaunchPad eval board, which is what was priced at $4.30).

Yeah I loved my LaunchPad. I bought like 20 and handed them out like candy at school

Were the LauchPads or the ST 'Discovery' line of super cheap eval boards first? Those were brilliant for getting the part in people hands.