74LS157

$2.99
74LS245 / 74LS245N replacement chip,DIP-20, Octal Bus Transceivers With 3-State Outputs.

74LS244

$2.49
SN74LS244 replacement chip. DIP-20, Octal Buffers and Line Drivers With 3-State Outputs

74LS273

$2.49
74LS273 replacement chip. DIP-20. Octal D-type flip-flop with clear.