It is pricey. It’s worth working out if the Istanbul card would save you money (it doesn’t cover everything).
we were there a few weeks ago. Loved it. We stayed near the blue mosque, hotels round there have small rooms, small lifts, and are expensive. It’s quiet round there at night and you have to be a bit picky about where you eat…lot of tourist trap restaurants. Basically ignore anywhere with someone trying to encourage you in.
if I went again I’d probably stay in Beyoğlu. Less touristy better choice of places to eat.
the public ferry across to the Asian side is great.
we took the public ferry up the Bosporus as well. Easy to do.
when I first went a few years ago you could go right I. Hagia Sophia and it was incredible, now you can only go upstairs and it’s being renovated….it wasn’t the same.
we got a guide through the hotel, who was very good, it’s easy to arrange with get your guide.
i liked the topkapi palace and the Dolmabahçe palace a lot. Get to both of them early, at opening time.