Sure

"Sure" means "yes".

A: Hey, can you help me with this?

B: Sure.

 But "sure" is more casual than "yes".

If you just answer "yes" to a question, it can sound as if you are angry:

A: Hey, can you help me with this?

B: Yes.

A: Uh... Are you annoyed or something?

"Sure" is similar to "of course". Both suggest that it's obvious and expected for the answer to be "yes".

A: Will you come to my graduation?

B: Of course!

"Of course" is a stronger response and more positive response than "sure".

I'll take (something)

"I'll take ___" is similar to "I'd like ___"

I'd like a beer, please.

I'll take a beer.

"I'll take ___" is better to use in someone's home because it's friendlier-sounding. "I'd like ___" sounds too much like something you'd say to a waiter.

whatever you have

Use the word "whatever" to talk about anything that fits into a category or matches a description:

You should just do whatever they ask of you.

Stop whatever you're doing and listen up!

"Whatever you have" means "anything". If you say "I'll take whatever you have", it means that you don't care and you'll accept anything. This makes it easy for your host if they don't have many choices.