I disagree that if you're into ecstasy you'd neccessarily be disappointed with cocaine.
As someone else stated, it definantly is something you have to be into to enjoy.
I was really into ecstasy for a while, and while I was into it, I never really appreciated coke. I didn't quite get the high. It was like "okay, my nose is numb, I've got a rush of energy, I'm not 'high', this is kind of stupid".
The first thing you need to know is that coke isn't a drug you just use once or twice in a night. Buying $20's is a complete waste. First of all, if you're getting it powdered, it's cut to hell. Second, it's not ecomonical because thirdly, as I stated above, it's something you do over the course of several hours during a night.
I stopped using ecstasy because after a while it was giving me tons of problems such as anxiety attacks, insomnia, lack of appetite, memory loss and it completely exaccerbated my bipolar symptoms. I don't enjoy being fucked up like that anymore. I like to be functional.
Cocaine later became a great alternative to rolling for me. So I'll tell you why and explain what the high is about and like at the same time. If you really want to get something out of it, it's something you take in a social setting with friends. I don't find it at all enjoyable to use alone. You take your first line or two, you get this great buzz of energy and then you start talking. As those lines wear off, you take more. You get more wound up in the conversation, which is usually good conversation. You get some empathetic feelings and typically feel close to the people you're with and get completely wrapped up in your discussions. You keep going for a while and now you feel like a million dollars. Use some more. Eventually you will "get there". It's hard to explain, but at a certain point when you'e consumed so much you reach this ultimate euphoric state. The problem is now you're not going up anymore. Instead you're taking lines to sustain the peak. Now the bad side is the come down. Either you'll run out or you'll need to go to sleep. And when you start coming down, for as good as you felt, now you feel equally horrible. You get desperate and you'll want to do more as you being to feel like shit. The comedown is the only reason why I don't use coke more than once in a bluemoon.
As far as doses go, there is no real standard for a dose of coke, because it really depends on how much you have and how far you want to go. Also the strength of coke varies GREATLY depending on how much it's cut. For a first time, I think a half gram would be fine. Say you were going to do it with a bunch of people, you could get it for less buying a larger quantity and make it so everyone is getting at least half a gram. As for what to pay, it's hard to say. The price usually has little to do with quantity. Coke dealers tend to be weird and one night may charge $50 for a gram then the next night charge $80 just because they feel like it. I've bought grams for $100, which seems high, but the quality was so great it was totally worth it. But I would NOT advise anyone to pay nearly that much unless you had some experience and knew it was top grade stuff.
And as for addiction, I think getting hooked on cocaine is almost as difficult as ODing on it. After you take your first line, you will CRAVE the stuff the rest of the night. But for most people it's not something you want to do daily. Once you go to sleep and wake up again you probably won't feel like doing it right away anytime soon. There are exceptions, though.