Learn Hardcore Japanese: ryoukin to zeikin wo goukeisuru to, koutuuhi mo irete mo yasui to omoimasu. - When you total the fee and the taxes, I think it’s cheap even including transportation costs.

料金と税金: と = “and” (joins exactly two items).
合計すると、: と = conditional “when/if,” often implying a natural/resulting consequence.
安いと思います: と = quotative “that,” marking the content of the thought: “I think that it’s cheap.”

What nuance does the conditional と in 合計すると have compared with たら, ば, or なら?

合計すると: “When you add them up, (as a natural result) …” Neutral, often used for general truths or predictable results.
合計したら: “If/when you add them up (in that specific case) …” More event/situation-focused.
合計すれば: “If you add them up …” More hypothetical/conditional and a bit formal or written.
合計するなら: “If you’re going to add them up / If the condition is that we add them up …” Assumes a premise you’re considering.

Why are there two も’s in 交通費も入れても? What does each one do?

First も in 交通費も: additive “also/even,” emphasizing transportation costs in addition to the fee and tax.
Second も in 入れても: part of the pattern V-て + も meaning “even if.” Together: “Even if you also include the transportation cost.”

Is 交通費も入れても redundant? Can I drop one of the も’s?

交通費を入れても: Very common. Keeps the “even if” meaning; no special emphasis on “also.”
交通費も入れても: Adds emphasis that transportation is an additional item on top of the others.
交通費も入れて (dropping the second も): Changes the meaning to “including the transportation cost” (no “even if/still” nuance).

Where did the を go after 交通費? Shouldn’t it be 交通費を入れて?

When you use も, it replaces particles like を/が/は. So 交通費を入れて becomes 交通費も入れて when you want the “also/even” nuance. You don’t use を and も together there.

What exactly does 入れて mean here? Is it literal “put in” or “include”?

Here 入れて from 入れる means “to include (in the total).” It’s the figurative “put in (to the calculation).” It’s very natural in everyday speech for including costs.

Could I use 含めて or 足して instead of 入れて? What’s the difference?

含めて: “including” in a more formal/explicit sense of inclusion. Example: 交通費も含めても安い.
足して: “adding (numerically).” Focuses on arithmetic addition. Example: 交通費を足しても安い.
入れて: Everyday, flexible “include/put in.” All are acceptable; choose based on tone and nuance.

What is the subject of 安い? What exactly is “cheap,” and who is thinking it?

Japanese omits obvious subjects. The understood subject of 安い is “the total amount (after the additions).” The thinker is “I” (implied by 思います). You could make it explicit: 料金と税金を合計すると、交通費を入れても合計金額は安いと思います。

Why is it 安いと思います and not 安いですと思います?

Before と思います, use the plain (dictionary) form of the predicate:

i-adjectives: 安いと思います (not 安いですと思います).
na-adjectives/nouns: 便利だと思います, 学生だと思います (use だ, not です, before と思います).

Do I need と思います? How does it change the tone?

…安いです。 A direct assertion: “It’s cheap.”
…安いと思います。 Softer and more polite/hedged: “I think it’s cheap.” Common in conversation to avoid sounding too blunt.

Is the comma after と necessary? Are the spaces normal?

The comma after …合計すると、 isn’t required but improves readability.
Spaces between words are for learners. Standard Japanese writing doesn’t use spaces: 料金と税金を合計すると、交通費も入れても安いと思います。

Why use と to join 料金 and 税金 instead of や? What’s the difference?

A と B lists items exhaustively: exactly A and B.
A や B lists non-exhaustively: A, B, and things like them. Here, 料金と税金 means specifically those two. 料金や税金 would imply “fees, taxes, and the like.”

Could I say 料金と税金を合計して、 instead of 合計すると? Does that change the meaning?

合計して、 is a sequential “and then/after,” while 合計すると、 is a conditional “when/if (you do that), then (result).” Both can work, but すると better highlights the cause–result relationship.

Is 合計する the best verb here? What about 合わせる or 計算する?

合計する: “to total/sum up” (most direct for summing amounts).
合わせる: “to combine/put together.” More casual; fine in speech: 料金と税金を合わせると…
計算する: “to calculate.” Broader math sense; okay but not as specific to summing items.

What does ても imply about “still cheap”? Do I need words like まだ or それでも?

The pattern V-て + も already implies “even if,” which carries a “still/nevertheless” feel. You can add emphasis with それでも or なお:

交通費を入れてもなお安い
それでも安いと思います They strengthen the contrast but aren’t required.

Can I use 入る instead of 入れる?

入れる (transitive): “to include (something).” You control the inclusion: 交通費を入れても安い.
入る (intransitive): “to be included.” The cost ends up included: 交通費が入っても安い. Both are grammatical; choose by whether you frame it as actively including or being included.

How do I read the kanji in this sentence?

料金: りょうきん
税金: ぜいきん
合計する: ごうけいする
交通費: こうつうひ
入れて: いれて
安い: やすい
思います: おもいます