Still getting caught up on what I missed while I was away, but I’ve got an answer to this one: となると = when it comes to, if it’s true that. It’s in the Intermediate grammar dictionary.
So, “If it’s true that it’s 1000-yen milk, I’ve gotta give it a try”
1000 yen is… rather a lot for milk.
Wow! That is great! Thank you so much @Belthazar!
And yes, I’ve never seen 1000 yen milk on sale anywhere! (But then again, I’d hardly go looking for it either! lol!)
Having trouble in page 127 and later in page130 with しゅっぱーつ. Not a first time i’m having trouble looking up words that have "ー” prolongation mark, either i now(guess) it or am complete clueless.
It’s 出発. Often if you can’t find it with the elongation mark replaced by a vowel, then try dropping it altogether.
Page 127
よし according to Jisho is “good”, but I suspect that this is Yotsuba super-contracting one of her favourite words: よっしゃ！
I remember よっしゃ！from vol 3, page 9, when she goes to the park to look for an おみやげ for あさぎ and according to Jisho it means “gotcha; alrighty; got it; OK”.
Here in vol 6, page 127, Yotsuba is again using the word (if it is indeed the same word) just as she sets off on a mission!
I’m confused .-. Where did you get よっしゃ from in this message?
Page 127. I’m taking a wild guess that よし is the same as よっしゃ！
But are you having trouble with the word? Since you quoted kodvin’s message I thought you were trying to answer his question.
Other than that, I wouldn’t say the same, but really similar. 
Yes, I was! There is only one word on page 127, and so that’s got to be the one he’s asking about there! Belthazar has already answered the question about 出発 on page 130!
Oh, I thought he meant 出発 for both, which are in page 128 and 130. 
Oh, I see! Yes, I think you might be right! 
Oh, I didn’t see the mention of 127. I pretty much just read the hiragana and nothing else.
Okay! If my calculations are correct, I didn’t read any Yotsuba this time, so time to fix that!
So, page 6: お城作った, got it. nvm
玉も乗った the ball she put on the castle
飲みかけのジュースはリサイクルじゃないでしょう！飲め! 
Hahaha! 毎年ほかのシャツがある 
お父さんも同じことを言った（笑）
Well, that was really fun. 
Great, thank you
Oof, I am getting more and more behind on this. I really need to start catching up.
Page 140
Yotsuba is looking at the road sign and imagining what the characters are saying:
とーちゃんじてんしゃかってー
Dad, will you buy me a bicycle?
あれはおとなようだ
I’ve forgotten what あれは is and can’t find it, おとな means adult, and I’m having trouble with よう. Is it 用? Is he saying that bicycles are only for adults?
I guess so given the next two frames.
Thanks for any help anyone can offer, and what an amazing chapter! Such an adventure!
あれ = that. これ, それ, あれ
And yeah, Xよう = for X use only
Thank you so much! (Fancy forgetting あれ! The more I study, the more I forget!). Thank you again!
Page 142
Yotsuba sees Fuuka on her bike up above and calls out (to her?)…
はしをわたらないと
はしを - 橋を - the bridge (and を particle)
わたらない - 渡らない - the negative of 渡る, to cross over; to go across
と - this is where I have problems
I guess she is saying “don’t cross the bridge!” (ie, wait for me) but I don’t understand that と. It looks like the conditional と of “if” or “when”, but I can’t see how that fits. Any ideas? And thank you!