Language Learning

(Not the person you originally replied to, but also German native speaker)

Ich gehe gern in das Theater im Wochenende, obwohl Hamilton zu teuer ist! Hamilton ist mehr als $500! Welche Theaterstück ist billiger?

This is 100% understanable, so: good job! There's a couple things you could improve though. The first two are small grammar mistakes:

[...] im Wochenende [...]

It's "am Wochenende". Just like in English, where "in the weekend" would probably be understandable, but "on the weekend" is correct, here it's "am Wochenende".

Welche Theaterstück ist billiger?

Again, completely understandable. However, "Welche" needs to be in the Genitiv and Neutrum hier, i.e.: "Welches Theaterstück ist billiger?". I can't really know where the mistake came from, but as far as I can tell, the options are either: you assumed Theaterstück is Feminin (e.g. "Welche Frau" / "which woman" would be correct, since "Frau" is Feminin / "die Frau"), or you intended to ask the question in the plural ("Welche Theaterstücke sind billiger?").

With those two changes, your sentences would be completely grammatically correct.

Now I got a couple of nits. They do not make the sentence "more correct", just "more natural".

Ich gehe gern in das Theater am Wochenende.

Due to the word order and the use of "in das" here, the emphasis is (slightly) on "that theater". I.e. it sounds a little bit like you are trying to say, "I like to visit this specific theater on the weekend". I assume you wanted to express a more general "visiting a theater is something I like to do on the weekend", in which case I'd suggest swapping the word order around a little, plus changing "in das" to "ins":

Ich gehe am Wochenende gern ins Theater.

The word order is a little more natural in German, but the main thing to note here is "ins". This might seem similar to a contraction like "it is" -> "it's" in English, and I guess it kinda is similar, but "ins" does not carry the same connotation of colloquiality. Even in very formal written texts, I'd be very surprised to find "in das" used over "ins" (maybe excluding some very old usage of that phrase? Not sure tbh).

This is actually something I see very frequently with folks speaking German as their second language and it always sticks out a bit. So, rule of thumb: If the place you'd like to go to/into is Neutrum, contract "in das" to "ins" to sound more natural, even in written text. (The same is not true for Feminin places like Bakery/Bäckerei, there "Ich gehe in die Bäckerei" is correct and natural, and Maskulin places like Forest/Wald, where "Ich gehe in den Wald" also can't be contracted.)

Next point:

Hamilton ist mehr als $500!

Small thing first: In German, the currency symbol/word goes after the number (e.g. 500€), though I'm not sure if that rule applies to $ in German. But €500 would definitely be incorrect.

The other thing I wanted to point out is the usage of "mehr als" here. It's not wrong. It just doesn't "vibe" with the verb is/ist to native ears. "Hamilton kostet mehr als 500€" would sound completely natural, just the "ist mehr als" sounds off because those words are rarely if ever used in that combination. The more natural alternative would either be to use "kostet", or simply:

Hamilton ist über 500€!

Although, now that I'm writing it, I'd personally recommend:

Karten für Hamilton kosten über 500€!

or

Hamilton kostet über 500€!

...but that is quite a lot of changes to your original sentence. So: all the options are fine. Your original is grammatically correct. I'm just nitpicking with a focus on natural-sounding-ness.

Final point:

Ich gehe gern in das Theater am Wochenende, obwohl Hamilton zu teuer ist!

Could you tell me what the English sentence/meaning was that you had in your mind and wanted to translate? If it's something along the line of "I like going to the theater on weekends, despite Hamilton being too expensive!" then disregard everything below this point.

However, if your intention was something more like: "I'd like to go to the theater this weekend, but Hamilton is too expensive!", let me know, then I have some additional thoughts on the sentence.