Translation:If you do not have any money, I will pay.
I disagree. That sounds like how a non-native English speaker might phrase it. "I'll pay" is much more natural, and it's still a 100% correct translation of the German.
"Tomorrow, I X" where X is a present tense verb is completely acceptable in both English and German (and Spanish and other languages).
For example, "Tomorrow I fly to Houston." "Tomorrow we play for the championship." etc.
from what ive heard (and im no native speaker)
,,falls" is more like "in case" and ,,wenn" just plainly "if".
for example, falls cannot be used with could, would, should, and the like. similarly, in case cannot work either.
"in case I would do that" sounds weird. similarly, the german equivalent with falls would sound weird.
however! "if i would do that" sounds better, and using wenn here would be a lot better.
this is basically just summarized from this article tho: https://yourdailygerman.wordpress.com/tag/falls-vs-wenn/
"In case" has a different meaning here. "If you don't have any money, I'll pay" indicates that you will pay unless you don't have money, in which case I'll pay. "In case you don't have any money, I'll pay" says that I'll pay regardless of whether you have money, to avoid the possibility that you're asked to pay something you can't afford.
"In the event that" or "in the case that" might be closer.
Sorry, but I can't agree. I've jsut read and reread the article you cite and nowhere does it say: "If I would.." and I'm not surprised because in English "if" + would, could etc is a no starter. The "if" goes in the hypothetical part of the sentence: "If she passed the exam, I would eat my hat." the ''would'' goes in the result. Thanks for reminding me of the "wordpress" I've been neglecting it lately.
to me, falls sounds wrong because it sounds hypothetical https://yourdailygerman.wordpress.com/tag/falls-vs-wenn/
That's why it's a bit more polite, in this (assumed) case. If you say "Wenn du kein Geld hast", it sounds more likely that the person doesn't have any money (or you already know that they don't have it), and maybe you didn't expect them to have money in the first place. It can potentially tend to mean "Since you don't have any money, I'll pay".
"Falls" is closer to "Just in case you should have no money at hand right now, I offer to pay for this", but since you know you're with a person of honour who wouldn't go to a restaurant without having an appropriate amount of money with them, you're sure that if in fact they have no money, it must be because they've forgotten their wallet (they're probably searching for it right now), and you politely offer to help them out of that tight spot.
Of course, "wenn" isn't rude here either. You can use both "wenn" and "falls".
Which is your language? My native language is English (Northwest US.) My sense is that we need the "will" here. As for German, this should be present tense, as it is. Perhaps this chapter will be helpful.
Basically, German often uses present tense for situations where we would use future in English.