Below you see the personal pronouns with accusative and locative case suffixes:

Nominative	Accusative	Locative
ben	beni	bende
sen	seni	sende
o	onu	onda
biz	bizi	bizde
siz	sizi	sizde
onlar	onları	onlarda

As you can see, we can form these by just adding the suffixes (y)İ and DE after the pronoun. The only exception is that the third person singular uses n as a buffer letter, before the suffix follows.

Below are some example sentences. Note that the locative can also be used for expressing possession.

I love you.	Seni seviyorum.
We are eating at his place.	Onda yiyoruz.
I have no money.	Bende para yok.
You have the pen.	Kalem sizde.
He is beating her.	Onu dövüyor.

Be careful with the response to Seni seviyorum. You should say Ben de seni seviyorum and not Seni de seviyorum. The sentence Seni de seviyorum implies that you love others besides your partner.

Breakdown of (Biz) onda yiyoruz.