Using this method, I'll show you how you can access 5 (or even more) inputs through 1 Arduino pin. These buttons will only be read correctly if only one is pushed at any time though.
As we go through it I'll explain whatever background info you need to know, so as long as you can blink a button, read a switch and read an analog input, you'll be fine. If you can't do any of these, I'll point you in the right direction in the relevant steps as well.
Step 1: Parts List
This is pretty simple:
1 x Arduino (Obviously)
1 x 100K Resistor (Brown Black Yellow)
1 x 1K Resistor (Brown Black Red)
1 x 10K Resistor (Brown Black Orange)
1 x 33K Resistor (Orange Orange Orange)
1 x 68K Resistor (Blue Gray Orange)
4 x Push button switches
Some wires to connect it all
You can use any push buttons you might have lying around, and the resistor values are not critical. More on this later.