No recommendations as I didn't like the tailor I went to in Hanoi.

However, to answer the other parts of your question. The cost depends on the quality of fabric you choose, on top of the tailor fee (i.e. you can choose to purchase fabric at another place, but who has the time) - I've paid $250USD or so, but I was choosing the lightest fabric they had, which was, how fittingly for the shop, also the most expensive.

And yes, you can get wool suits. All the suits I've seen in the tailor shops I've been to were either wool or linen. No silk suits, as I recall, so no worries about that.

you could try Co, in Big Church street, next to Ca Phe Mocca

Two things about tailors and suits:
1. Bring one of your own suits and let the tailor copy the style. This is usually the fastest way to get things done and to make sure you like the style.

2. Don't get lured in by labels: Even if the label on the fabric says "Super 120s, Cashmere" it is usually neither a 120s (or whatever) nor Cashmere (but you can see that right away).

The best tailor I ever experienced is TAM (0989098903), friendly, competent she comes to your house and just needs some items that fit you the best way to copy it. Try Tam, you will not be disappointed. She has made more than twenty shirts for me, nothing to complain, I`'ll always go back to her and ever recommend her.

I recommend Đức Nhuận on Cầu Gỗ Street (I dont remember the number but it's pretty easy to find. From the digital board by Hoan Kiem Lake, skim the street where there are a bunch of shoe shops, you'll see the only tailor among them)

The prices there are not cheap, I think reasonable ($200 on average). You will have to come and try it one time before the tailor finishes your suit. it takes about 10 days until you get your suit.

My husband got his wedding tux made there and other business suits. We were recommended by my brother and they are all happy with the tailor.

Hope this helps.

I'm not sure Miss Tam (above) is comfortable with making suits, but its worth asking her. She has certainly done an excellent job of copying several different items (men's and women's clothing) for us.