Look for a single rail dac, they exist.
racemaniac: What exactly is the simplest DAC you can come by that's easy to use? .... my purpose.
simplest -- see R-2R resistor ladder network (digital to analog conversion, or DAC)
Anyway, you only get something for nothing on "Instructables".
I would recommend NOT using a DAC0808 if you can avoid it, for 3 reasons:
Parallel input uses a lot of pins. An SPI DAC will only use 3 (Clock, Data, and Chip select).
It requires a negative voltage to bias the output circuitry. My DAC0808 datasheet says it requires a minimum of -4.5 V on Vee. Grounding it won’t cut it.
It is a current output DAC. Measuring the open-circuit voltage on pin 4 will tell you nothing. You need something to convert the current into a voltage. A resistor works, but gives you negative voltages because the device sinks current (ie, pulls it in). The op-amp transconductance amplifier in the example circuit will give you positive voltages.
Use an SPI DAC from Microchip (http://www.mouser.com/Semiconductors/Integrated-Circuits-ICs/Data-Converter-ICs/Digital-to-Analog-Converters-DAC/_/N-6j74u?P=1z0z63x&Ns=Pricing|0). They’re cheap, can have up to 12 bits resolution, come in single and dual packages, and have a direct voltage output instead of a current output. The only downside is that they’re slower than parallel DACs (Not a concern at Arduino speeds), and harder to use since you can’t just hook up some switches, you need a microcontroller that can shift out the data.