Merideth, yes you can self publish your book of poetry as an ebook and you won't even need an ISBN for it if you aren't planning on selling it anywher except from your site, and some places that let you sell your ebook at their sites don't require an ISBN either.

You can offer it as a PDF ebook only. You can get yourself an account at PayPal, if you don't already have one, and accept payment through them. They have a "Buy" button that you can code to place on your website for purchasing purposes. I have never had a problem with PayPal.

What you could do is to have it for payment through PayPal and when you receive notification that someone has purchased your ebook, you would send them an email with the ebook as an attachment.

There is a way for it to be put onto your site and automatically downloaded when someone buys it but I am not really up on that.

I have my Star ebooks set up to sell through PayLoadz (with PayPal for payment) and the uploaded ebook is at PayLoadz. When someone buys it, they automatically receive an email with a download link and I don't have to do anything.

There is a site called eBookAd.com where you can place your ebook for sale and not have to handle anything. But they take a percentage of your purchases for handling it. I used to use them but I had a major problem with them recently collecting my money.

I hope this helps.