Ferry boats (Feribot in Turkish) are everywhere in Istanbul. I mean EVERYWHERE. And they are cheap to use. You can get a ride across the channel for $1.50 (USD, 3TL). I got on one thinking I was crossing, but in fact it was a tourist boat that just did a big circle around the city for sightseeing. It was significantly more expensive, but thankfully I was able to transfer to a boat that was going to Uskudar (the Asian side) for free.
I found a nice spot on the Asian side that was basically a cafe on the water front and spent half of my day there sipping on tea and photographing the bustle around there, waiting for the light to get soft and gorgeous (which it did in epic fashion). I took the boat back over this morning there to enjoy the view (and a Turkish coffee...) while I read. It was worth it.
I head to India tomorrow. Here are a few more that I haven't published yet from yesterday on the Asian side of the city. Enjoy!