I've written several ebooks over time and am always interested in looking at different ways of selling them. The free ones are easy to deal with: I just upload them to my website and tell everyone where to get them. Ones for sale are more complicated, because you have to take into account other things, like:

Sales tax, in my case VAT.
Temporary URLs -- otherwise some people would just post the URL and effectively make the book available free of charge.
Shopping carts which are automatically updated as purchase requirements change.
A variety of payment methods.
An automated thank you email and/or redirect to a 'thank you' web page.
Bundles/deals, should one wish to offer them.

I've just started a free trial of e-Junkie. I've read a couple of articles in which people are singing its praises. One attractive thing is that, unlike many services, it doesn't take a transaction fee. Typically, that runs at a fixed amount, like one dollar, plus a percentage. That doesn't sound much, but if you want to make the books available at a fairly low cost you will find that hard to do: don't forget, PayPal, or whatever payment method you use, also takes its share.

E-Junkie was easy to set up. I only needed to look at two things in the documentation: how to enable the VAT charge for EU residents, and how to set up the API settings for PayPal to handle payments. And that was only because I didn't look at the set-up page to start with. I have to say that so far this is the easiest set-up of this kind that I've implemented.

The transaction side of things appears to be just as easy. When you make a purchase you are redirected to a page with a download link straight away, and you also receive an email with the same information plus a receipt for your records.

Now that I have set up the PayPal link, and other 'fixed-cost' items, uploading new ebooks should be easy.

Fingers crossed!

It seems to me that this sort of service could have use in a school setting too. Some schools sell DVDs of school plays and that sort of thing, to raise money for charity or to offset the cost of school trips for poorer pupils. At $5 a month for the lowest entry level, e-Junkie may be just what's needed. I notice, for instance, that you can set up tax rates for individual countries and even individual states in the USA. It may be worth giving it a whirl for a week.