You need to be able to create them youself, by starting from simple Japanese then working your way up. There's another sentence there that you can probably already say based on your ability so far:
"I don't need a plastic bag"
Plastic bag = fukuro
Need = irimasu
Don't need = irimasen
Therefore "I don't need a plastic bag" is "fukuro ga irimasen". I say this on a near daily basis in Japan