Where have you search, or better what do you consider cheap?
Referencing 16F877A in 100 qty:
Digikey ~ $5.40 - $6.00+
Microchip ~ $4.98 - $6.00+
Mouser ~ $4.68 - $6.00+
Futurlec ~ $5.30 +
Most large selling distributors ~ $5.00 average. If you want cheaper than the already 100 qty price break...