Parts List:

Specialist Parts
The following items may be obtained from http://www.adafruit.com and/or http://www.aliexpress.com:
1 x SI5351A Clock Generator Breakout Board 
1 x Rotary Encoder 
1 x 16x2 I2C LCD display
1 x ATmega328P microcontroller
1 x 16 MHz crystal

Power Supply:
The following components should be available from your local electronics store:
1 x Vero board
1 x LM7805 voltage regulator
2 x 22uF electrolytic capacitors
1 x 470 ohm resistor
1 x LED
1 x power connector

Arduino:
The following components should be available from your local electronics store:
1 x 28-pin ATmega328P socket 
2 x 22pF ceramic capacitors
1 x n/o push-switch
1 x 10K ohm resistor
1 x SPST toggle switch
Header pins with 0.1 inch spacing

Approximate cost: $50