I agree that Duolingo can be rather inconsistent, and I think your best bet is to just translate as simply and directly as possible, generally using the present simple tense in English. I.e - "I pay", not "I'll pay" or "I am paying" or "I'll get this" (the latter being completely idiomatic anyway).
"Please, I pay" sounds pretty bad and is a common mistake made by English learners if you imagine it is a one-off event, but it does make perfect sense if it is a reoccurring event. E.g You are the father of the family and every Friday, with your wife and kids, you go to a restaurant. This week your son's friend comes along and at the end gets his wallet out and says "Here, please take this for my part of the bill!"... what would you say?
Although you might choose something else in reality, "Please, I pay" would definitely fit the bill.
I have learned that the present tense can be used to describe an action that will occur in the very near future. The question is how far into the future can you use the present tense to describe an action in this manner. Incidentally, I have heard "I'll pay" used many times by others and myself as well. I don't think that I have ever heard the awkward "I pay" used in this context.
It is not really about time frame, though I can see how that might enter into some contexts. The point is that Spanish present tense fits a lot of situations that English shifts to another tense. In terms of future, the idea is that the future event/action will occur with some certainty. You could use the Spanish present tense to say you will see someone in two years if you truly intend to see them then.
The reason I say that I can see how time frame might enter into this is because the more distant the future, the less reasonable it is to assume it is certain. It makes more sense to use present tense to say "I'll see you tomorrow morning" than to say "I'll see you in two years time."
I don't really understand your question. The Spanish sentence is perfectly correct and works as is. If you're talking about the English translation, Duo accepts "I'll pay" as well as "I pay." At least it does as of 9/2017. There's actually quite a lot to be learned here from thinking about it both ways (i.e., the meaning of the present tense when used in Spanish).
I agree, "Please, I pay" doesn't sound right in English. Maybe it depends on what you enter, because the solution offered at the top of this page is "Please, I will pay." You don't say what you entered that triggered the correction to "Please, I pay." If it was something Duo thinks is expressed differently in Spanish, it may have presented the most literal translation to avoid further confusion. Just look at the number of people complaining that "will" is not in the Spanish sentence.
With respect, this happened 7 months ago. I can't remember exactly what I typed in, but the "correct" answer at that time was definitely "Please, I pay", which prompted me to add to this thread. I'm not the only one who mentioned this phrase. and I got a couple of upvotes, so evidently some people agreed with me at the time.
I'm sure you're right and I'm not debating that. Clearly, Duo has heard from enough users like yourself that they have changed the #1 solution.
Personally, I think the bigger lesson is that the Spanish present tense is often used where we would use the future tense in English. If the exercise were reversed and we were asked to give a Spanish translation to "Please, I'll pay," I suspect, unfortunately, most will insist it should be, "Por favor, yo pagaré."
This is a very typical type of conversation one would witness within Hispanic culture. Especially in Spain, when a group of people go to dine, the conversation goes with someone offering to pay, other people interject but the first person is usually given the "honor" of paying
In context would this be the equivalent of "Check, please" That is If I were translating "Check please." in a book would. "Por favor, yo pago." work? Or if I were in a dinner and held up my hand and said. "Por favor, yo pago." would they give me the check or look at me funny?