Although this won't be the last time that you learn about the particle も, this lesson will introduce you to its most important usages.
も means "also/too." When it's used, it cancels out the particles が, は, を. However, you will still see examples of をも in old-fashioned contexts. Similarly to は, も emphasizes sheer lack in negative sentences, but in positive statements, it is heavily used to simply soften the tone of a sentence.
The weather's good, too.
2. ぼくもお腹が空いた。(Idiomatic; male speech)
I'm hungry too.
To not move even a centimeter.
There's rain in Tokyo and in Kyoto.
What a success, it was a great success.
That computer doesn't even cost 50,000 yen.
I waited at least/about five hours.
Particle Note: In Ex. 7, も here implies perhaps a much longer wait, that is, you've already waited "at least five hours" and the wait has become unreasonable. This same logic can also explain Ex. 6. Here, it's implied that the cost of such a computer doesn't even exceed 50,000 yen. Since this equates roughly to $500, we can imagine that any much higher than that would be an exuberant price without the quality of the PC being far higher than standard expectations. In both cases, も is seen after some counter phrase. Its interpretation is then influenced by whether the sentence is in the affirmative or negative.