Hey Loki,
Welcome to pc!

Yes, it definitely depends on the hospital. I've been to the ER 4 times for this, 3 times for ideation and once right after an attempt. As for just the ideation times, one hospital put me in a completely bare room with nothing but two chairs and cameras on the walls, a different hospital another time gave me a bed and a minimally furnished curtained area, and in a different hospital they put me on a bed in the hall because they were so crowded (many hours later I got a real room). Each time took at least 5 hours.
They will assess you with a boatload of questions to determine if they should send you inpatient or if you are safe enough to send home with a list of outpatient resources. They usually take the inpatient route, especially if you're self-admitted. In fact, in order to go inpatient, almost always you have to be admitted through the ER. And it will be expensive, but a whole lot of places have special financial aid that can help you with the cost.

I'm so glad you are thinking about getting help for this before things go too far south. Early intervention is critical for any health-related issues, including psych ones. Please do take that step and admit yourself. But also please please please know that you will only ever get out of inpatient therapy what you put into it. It can make no difference or a huge difference, that's completely up to you.

Good luck, my friend! I truly hope things work out well for you.