Studio type apartment, but by myself, or a two-bedroom apartment, but with my sister?

Don't get me wrong, I love my sister. But there are just some things you don't share with her anymore. And we do get on each other's nerves (probably because of mostly sharing the same bedroom since we're still kids).

I prefer to have a small studio type apartment by myself, but shouldering all the costs. Here's an estimate (in pesos):

a. Rent: Hopefully around P4k
b. Water and Electricity: Hm? Around P1k - P1.5k pero month.
c. Food: This is a tough one. I love eating, see. So let's say P2k/month.

This is living expenses. I still haven't considered how much would I need to spend initially, like appliances, furniture, rent deposit... *hurls at the cost*

So the total living expenses is around P7.5k per month. *hurls some more*

The only practical option for me is to share a pad with my sister, and hopefully there are two separate bedrooms, because:

1. I refuse to be on the top bunk, again. Being the younger sister, she always bully persuades me to get the ones with the lesser value. And I'll always hate her for it.

2. Boyfriend. 'Nuff said.

3. Private space for stuff, like decorating, having my own rules in my bedroom, and I can have my friends sleep there if need be.

Monthly estimates:
1. Rent: P5-6k (two bedrooms, one bathroom, sister prefers kitchen area)
2. Utilities: P2k
3. Food: P2k (sister knows how to cook. I don't. So this is a plus on living together).
4. Possible Internet: P1k

Total: Around P11k or P5.5 per month. That's P2k less than living alone.

My sister and me plans on scouring Krus na Ligas area (near UP) because it's the most accessible place we have from our workplaces (at least I only have to walk, sister needs to do short commutes). This will be our second attempt. I hope we are successful this time.