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.
Wording Note: This explicitly states cost (purchasing, repair, etc.). あのコンピューターは五万円もしない doesn't.
I waited at least/about five hours.
Particle Note: も here implies perhaps a much longer wait. も emphasizes the amount.