Moving to Istanbul! Need some advice!

Guys, I am looking forward to move to Istanbul at May and need some seriose answers!

1) I am looking for a flat (long term rent) at Galata area (2 rooms minimum for a price no more than Protected content or small house (can be any area) for no much than Protected content . Is it possible? Any web recommended? What the usual prices for a flat/houses? What's the best areas? Anybody got friends/relatives who interested to rent?

2) I am looking for a commercial space to open a small shop near Galata area (less than 30m2) what can be a price? can you recommend me any web for search? looking forward for any information!

3) Can you also share a step of opening a private limit company? What's is the easier way?

Thanks!