There’s a verb おごる for paying for someone’s meal (or drinks 
). So I think you could say for example 心配しないで、おごるよ。(“Don’t worry, it’s my treat”), or, to stay more polite (if you aren’t that close), and closer to your idea - simple おごりましょうか？ should work.
In either case, both 私 and あなた can be safely omitted, since they’re obvious from context.
じゃ買ってあげようか could work too.
This isn’t “oh, should I buy it for you then?” like it looks though. It’s just saying you’ll buy it. I’m not sure if you will have seen this grammar yet so I can explain it more if need be 
No dumb questions here! We’re all on our own journey
Thank you so much @adamstan and @xarde for your quick and helpful replies!
That was in the Genki vocabulary list and I even memorised it last night 
lol
If I have, I’ve forgotten it lol. Since both you and @adamstan’s answers avoided saying ‘for’, does that mean it’s not used for situations like this in Japanese?
The てあげる is the ‘for’ part of mine. おごる, I believe, instrinsically has the feel of ‘for’
Often. It can be kind of embedded in the verb itself (the verb has nuance of doing something for someone), or obvious from context. And since, contrary to English, it isn’t needed grammatically to make correct sentence, whatever is obvious, will often be omitted - especially 私 and あなた So if for example you say to your friend in this situation おごりましょうか? it’s obvious that it’s you who will buy a meal (you use voiltional form) and you will do it for your friend (since you are speaking to them).
@xarde @adamstan Oh right, embedded in the verb. Now I get it, thank you so much again to both of you for your help! 
This has the danger of sounding patronizing, so I would be careful with it.
A more straightforward version of this is 買ってあげる(よ), but generally this あげる is only appropriate with friends who are the same age/status as you.
大辞林 says さしあげる is commonly used when addressing people of higher status, so yes, I guess so. あげる can imply that one is doing someone else a favour, after all.
@e_w0205 I’m really not sure if 〜おう or 〜ましょう is polite enough, especially if it’s a ‘friend from work’ whom you might not know that well just yet. (I’m asking a more knowledgeable friend for confirmation, because I tend to split hairs even in my native language.) Here’s a sample conversation from the Wisdom EN-JP Dictionary under おごる:
I personally think that 奢らせてくれませんか (‘will/would you let me pay?’) or even 奢らせてもらえませんか (‘could I have you allow me to pay?’) would be more polite. Another possibility is an unfinished sentence like 私がおごったら（どうですか・いいですか）。(You can leave out the bit in brackets and just raise your tone so it sounds like a question. It would mean something like ‘How about if I paid?’) I think 私がおごってもいいですか。(‘Is it alright if I pay?’) is acceptable as well.
The main difference between these sentences and those proposed so far is that these sentences explicitly ask for/strongly imply a desire to know the listener’s opinion, meaning that you’re allowing your friend to make the decision independently without any pressure from you. That way, your friend won’t have to feel bad about refusing you (and won’t look bad if he/she decides to refuse your help). There’s less social pressure and risk involved.
I think everything that’s been proposed so far works, particularly if you’re with someone with whom you can be casual, but if you need something a little more polite for, say, friends whom you still aren’t that close to, I think you might want to consider these^ alternatives.
I have only seen ながら used with two verbs, but in this sentence it is attached to 残念. How does this make sense?
残念ながら、今日はとても涼しかった。
Unfortunately, it was really cool out today.
残念ながら in its entirety is an expression in its own right. Unfortunately, I’m not sure as to the etymology of it, or its connection to the ながら conjunction.
ながら is a particle that can attach to lots of things. The usage you mentioned with verbs is the most typical. As @Belthazar mentioned, 残念ながら is often treated as its own expression.
It can be used in an old-fashioned way to mean “even though” or “in spite of” as well. Here are some example sentences from a dictionary.
学生ながら読書もしない
Even though he’s a student, he doesn’t read
狭いながらも楽しく暮らす
Even though it’s cramped, I can live enjoyably
I don’t recommend using it that way, but you may encounter it in writing.
ながら can also be used with nouns and adjectives. Here is a bit of information about it:
http://www.guidetojapanese.org/learn/grammar/timeactions#Using_with_state-of-being
Thank you Belthazar, Leebo and NicoleRauch. I understand now.
It’s actually quite logical if you simply think of 〜ながら as meaning ‘while ~ happens/is true’. You can contrast the two states, and so you end up with either ‘while/at the same time as ~’ or ‘despite ~’ (because ~ remains true).
Yes, the link Nicole provided explained it in a similar manner. It made more sense than I initially thought. Thank you for your explanation.
So context is I got a present that will my beother really happy!
喜んでもらえると嬉しいですからね！
My guess is he is happy when receiving it, you will be happy because of it.
What does the と do in this sentence it’s the if part right? Anywho thank you in advance, can’t bloody wait to end the semester so I can study more grammar :confused 
Yes, と means if here.
If you can be happy, I’ll be happy
Is おろか used in casual conversation? Like 漢字はおろか、平仮名さえ覚えてないよ (I know it’s a weird sentence but…)
No, it’s a stiff expression.
Generally speaking, if you’re studying N1 grammar, it’s usually not used in casual conversation. Or it would probably have appeared sooner.
