The complete phrase is “kung sa bagay”, but it is not uncommon for us to just say it as “sa bagay”. As Dan Alexis has mentioned, its exact meaning may depend on context, i.e., other English words or expressions may be used in its place provided they fit the intended meaning. The translation I would give it may be found in the phrase itself: “if we are to be objective about it”. It almost always serves to introduce a rationale or a conjecture. Examples: Inubos ni John yung mga natirang pagkain. Kung sa bagay, wala naman na sigurong kakain nun. = John ate up the leftovers. If we are to be objective about it/I guess/Well, maybe no one is going to eat that anyway. - conjecture Si Paul ay sobrang gastador. Kung sa bagay, malaki naman ang kinikita niya. = Paul is a reckless spendthrift. Objectively speaking/However, he earns a high income though. - rationale Mary: Niyaya ako ni Jane na kumain kami sa labas. Hindi ako sumama kasi baka ako pa ang pagbayarin nun. Kilala na natin yun. Peter: Kung sa bagay... Mary: Jane asked me to dine out with her. I did not go because maybe I’d end up footing the bill. We know how she is. Peter: To be objective about it.../Well... - The implicit and intended meaning of the phrasal response is: "yes, most likely, so I would agree with you." – an agreement to the rationale, at the same time, based on a conjecture.

Kung sabagay best translates to the adverbs in any case, in that case, or even anyway. All of the above adverbial phrases (including the Tagalog kung sabagay) aim to explain or expound on a previous statement. In other words, when you use these adverbial phrases, you are saying that the previous statement is true and that you are in fact even adding to the veracity of that statement. If all you say is "kung sabagay" in response to a statement, it could be correct in the context of an on going conversation because your interlocutor already understands that you agree with him or her and is already cognizant of the reason or other reasons you have in mind for agreeing with him or her. In written form, it would be more properly written as "In any case....", the dots denoting the following statement that is implicit in the ongoing conversation. Here are some ways your sample text might be completed: "Shall we drop by the house or go straight to the grocery store? " "There's no need for us to drop by there anyway." "Kung sabagay (In any case / Anyway), wala naman tayong kailangan sa bahay / dala ko naman ang pera / mas madali tayong makakabalik kung uunahin natin ang grocery." If you want to end the conversation with a simple statement, the last sentence could be "Oo nga." or "Tama ka nga." Ending the conversation with "Kung sabagay..." as I said is acceptable in everyday conversation when both speakers know the implicit statement that follows "kung sabagay..." Otherwise, kung sabagay by itself (especially in written form) almost seems like a dangling modifier or simply, an incomplete sentence. (http://forum.wordreference.com/threads/kung-sabagay.1982747/) -- there are also other available translations (i think it depends on the context) such as 'oh well', 'as a matter of fact', and others.

Kung sa bagay really means, "After all, if we will really think about what is fitting, or what fits well, or what is the best, or what is the truth" . Or, "if you and I will really think about it,"....Or, "if you and I will see the bare and given facts...we will see that this or that is right after all."

Kung sa bagay, literally can be translated as.."if- in what is fitting" or "if -in what fits". The speaker could be saying, This is my opinion, but maybe the opinion that conflicts with mine is the better opinion. The speaker is saying something, but is submitting to the fact that he could also be wrong and the other conflicting opinion might be the right thing after all. The speaker is having second thoughts, or is deliberating on something and considering two differing opinions, then later submits cordially to the opinion originally different from his. The speaker might be saying, " Oh well, the other opinion mightbe the more fitting and the better one anyway."