It is possible to just go cold turkey but it's not just about stopping, you need to examine the triggers to your using and underlying reasons why you are doing this, then make changes there. So it can be difficult and outside help is often very useful.
I'm reminded of conversation I had with a group of reformed heroin addicts I know and they all reckoned giving up smoking was harder. Heroin is more addictive but you have to seek it out. If you want to quit, you get methadone and you cut other addicts out of your life so there's less temptation. However, before the smoking ban, smoking was a sociable activity. You could stop but someone was always offering them to you and, after a few pints, your inhibitions are lowered, so you accept one, then end up going to the cigarette machine and you are back on the hamster wheel again. That was the downfall of most of my friends who tried to quit smoking.
Unfortunately, cocaine is now a sociable drug. I turned up at the pub once and a guy I knew to chat to in passing was heading out and causally enquired if I wanted some coke as he was off to buy some more, as casually as if he was nipping down to the sweet shop. I've not drunk in 20+ years and I reckon I could sell my urine to athletes, so there was no reason I'd be interested but he clearly thought he was being friendly and helpful. So giving up isn't as simple as stopping, you will probably have to adjust your lifestyle to avoid other users because it is too easy to have a few pints and get offered a cheeky line and then you are back on it again.
Luckily I earn fairly well, so I’ve not got myself in any real money issues yet, but I need to stop.
It's not just about the money, most of my friends who are still taking cocaine I don't see that often any more because their lives are trainwrecks, not necessarily because of the cocaine itself (although cokeheads are poor company) but because of whatever demons drive them to it. You are aware that something is "missing" in your life and I suspect you aren't going to be able to unpick that without professional help.
And keep in mind it's not just about money this lifestyle has health impacts. I'm of that generation that saw cocaine become affordable and we aren't getting any younger. One friend had to have his oesophagus and upper part of his stomach removed about five years ago and I'm resigned to the fact that it won't be long before I'm attending funerals for those still using as it has a real impact on your health (especially your heart). I'll dig up a link to an earlier article about cocaine and drop it in as it goes into this in more depth.
edit: here it is