Struggling with the final steps!

Seems like I don't need to register or do anything other than
just get me a Paypal account.

You need to get a business license. This is a pain but is not hugely expensive. Do this, and you're on the right side of the law. Don't, and there's just that much more trouble if the IRS or the local equivalent come calling. I'd recommend just a DBA ("doing business as"), since your business is very small and doesn't involve any significant warehousing, manufacture, customer traffic, or liability.

You are going to have to declare your income in your tax returns. If you don't, you're breaking the law. (Even waiters and waitresses have to declare their tips.)

A person who sells a chair they don't want anymore (on eBay or anywhere else) is supposed to declare the income; but if you don't, it's unlikely that that one small transaction will be noticed, or that the law will think it worthwhile to pester you about it even if they do notice. But if you go into business buying and selling chairs (on eBay or anywhere else) then you are running a business and you are asking to be audited.

My recommendation: do it right. Get a business license, declare your income. I did it 17 years ago for my spare-time software business, and I've had 17 years of peace of mind as a result. I'm clean, and any audit will show it.

Well, now we're getting away from my comfort zone. :) My wife handles the taxes for our home business. But my understanding is the following:

1. As a DBA, you're really still just a private person, not a corporation. Your company does not have to pay taxes. (You do, of course.)
2. The taxes you must pay are of two kinds: income tax, and sales tax.
3. The feds don't charge sales tax; that's reserved to the states.

I don't think you need a Federal Tax ID, because you are a very small, unincorporated business with no employees. Your business income taxes are just included with your personal federal and state income taxes. But I'm not an expert, so I recommend you do more research. Here's a good place to start:

Internal Revenue Service: Starting a Business

You definitely need to get in touch with your State Board of Equalization, or whatever they call it in your state -- the department of your state government that collects sales tax from businesses. Make them aware of your new business, explain to them (in quintuplicate, I don't doubt) what you'll be selling and how you'll be selling it. You'll have to file separate tax returns for sales tax, and if your state is, or is like, California, you'll have to do it quarterly.

(Currently I don't have to deal with sales tax in my business, because my goods are all delivered by "electronic transer", i.e. by download -- I deliver bits. California does not (yet) charge sales tax unless you deliver molecules. But I used to ship product on physical floppy disks, and at that time we had to do the whole sales tax thing. You don't need to know that; I just explained it because I think it's interesting!)

Also, when I said you only have to pay income and sales tax, I was leaving out the relatively picayune local stuff, such as renewing your business license every year.

I'm going to stop giving advice now, because I'm getting out of my depth. As I said, my wife handles this stuff for us, and anyway neither of us are lawyers, so you mustn't trust what I say absolutely. But I wish you all luck with your venture, and I'll bet you'll have a ton of fun with it!