"Please help me buy some things."

Translation: 请帮我买一些东西。

[AndriesKir]

Is 一些 necessary here?

[nickicim]

it is as you want to specify that there are a few things (due to "some"). If you omit 一些 the number of things can be inferred to be one, some, or many.

[Tommy556270]

Yes it is. It means some, without 一些is 'buy things'

[Meeracidium]

请帮助我买一些东西
vs.
请帮我买一些东西
What's the difference? Is the first one incorrect?

[wenlai]

帮助 = rendering assistance.
帮我 can mean "do for me", The translation of "please help me buy some things" is actually slightly off. More often the translation should be closer to "please buy some things for me".

[oldschoolnoob]

My lucky guess is that both sentences are correct.

[rajul285485]

Is yi necessary. Can we say only xie instead

[wenlai]

It's very informal to leave it out. i.e. you mean to say whether this is accepted:
请帮助我买些东西
Generally speaking you would say it that way to people you're familiar with. It's not unheard of to say it to strangers, but it's very informal and you generally wouldn't speak like that with people you don't know.

[natmardec]

Is "yi xie" used for both singular and plural objects? Could you use it to mean only one thing?

[Tommy556270]

It basically means "some" and can be used for both singular and plural nouns.