We know minimum 5V DC is required for logic gate ICs. I do use an old phone charger as the power supply for simple logic gate experiments. Usually phone charger output is 5V DC.
I think you can also try it, if you want to do simple logic gate experiments at low cost. You can cut budget by not buying power supply. So check whether you can collect a phone charger.
My phone charger specifications are: input 100-240V AC, output 5V DC, 0.7 A
I have checked it using a voltmeter. It was about 5V output. So you can use it for your experiments where 5V DC is required. Of course do not use it when high amp is required for circuits.
First appeared on electronics-as-hobby.blogspot.com (2011)