grammar - past and present tense in one sentence?

I paid 30 dollars for the deposit and pay monthly rent.

What I want to write is "this apartment costs 30 dollar for the deposit, and I pay monthly rent(, which means I don't have lots of money.)"

I know in English we try to keep the tense in the sentence, but here, it's obvious that I paid the deposit in the past, and I still pay monthly rent since the apartment isn't mine.

Is it okay to write like this? I also tried to start the sentence with "the apartment costs...", but I wasn't sure if it's gonna work in English. Or could you tell me a better option?

Answer

It's fine to use the present and the past here. After all, that's what happens: as you say, you paid the deposit in the past and pay the rent in the present.

Tenses should agree in the same clause, but it's very common to have multiple tenses in the same sentence.

Although I was sick yesterday, I am fine today.
I’m eating the cookies that I baked this morning.

In your sentence, you are connecting two complete sentences with and, and again it's fine to have different tenses in them.

I paid $30 for the deposit.
I pay monthly rent.

The concern with tense agreement is important, but it doesn't mean that the tenses in a sentence have to be the same. It means that whatever the time relationship is needs to be properly and consistently expressed. This is an example of a typical violation of tense agreement:

Yesterday, I went down to the pool hall. I get on a table and start to play. Some guy asks if I want to play for money, and I say ok. We play for a while, and I win $100. I pretty much took him for all he had.

Here is a fairly detailed set of guidelines, with examples.