I've been a few times and I love Amsterdam because there's so many different sides to it. I've been with mates and it's been a good laugh, yeah you get high on a few joints over a coffee or have some hash brownies, wonder off for waffles then watch a funny sex show then go out to some of the bars and clubs. (most clubs in Amsterdam play EDM)
But on the on the other side it's absolutely beautiful with loads of history. Architecturally it's very interesting, and there are lots of museums to visit and general touristy things to do. A huge choice of lovely restaurants to pick from and a romantic canal ride is always a treat!
It's the kind of place you can go with the lads for the weekend for a good giggle, or go with your girlfriend for the weekend for a romantic get-away.
As for prices, it's pretty much like going to London. I wouldn't say it's particularly cheap, but it's reasonable. You go to London, you pay London prices, you go to Blackpool you pay Blackpool prices, you go to Amsterdam, you pay Amsterdam prices.
There are lots of bars/clubs/things to do... As someone before said, it will be as fun as the people you go with. If you want to watch some crazy midget sex show or some woman popping ping pong balls out of her pussy for a laugh, it's a funny experience and a good laugh. If you want to go out to a few bars and clubs in the night it's got that too. But, if you're after cheap booze and a shag, I'd go to eastern europe.
Feel free to ask anything.