So I own $1000 in bitcoin but I want to invest the remaining amount to accumulate a whole bitcoin. The prices fluctuates every second so how can I do this on coinbase? I believe this is called a market buy order and I've looked at the steps on how to do this but I think they're outdated or wrong.
I think in almost every market, if it still in buy / sell orders means you can buy / sell on that price and executed it. Or if you are in hurry, you can pick sell orders in it and pump it. But my suggestion is set your own buy order and left it until it is executed. I never trade in coinbase, but i think the system is same with other market.