In order to find a book on a certain subject, Aromatherapy in this case, just go to Google, type in the subject, "Aromatherapy", and press enter. After you have done this, go to the left hand side of the page and select 'Books'. This will narrow your search to just books about Aromatherapy. Now, you should see some likely titles such as "Aromatherapy: A Complete Guide to the Healing Art" or "Aromatherapy: a practical approach". Look through the books, reading the summaries until you find one that you like. Now, see on the right side of the page it says "Get this book" and has a list of retail store names such as Random House Digital Inc, Amazon, Barnes and Noble, Books a Million, Borders, etc. Click on one of the names to go to the company's website and purchase the book.
If you would prefer a way to compare the prices of the books in a fairly quick way, you can do a different Google search. This time, instead of selecting 'Books' on the left side of the page, you will select 'Shopping', which should be directly above 'Books'.
Now that you have selected that, you should see more books on Aromatherapy with an estimate of the prices next to the titles. To narrow down the price range, click on the drop-down menu on the top right of the page that says 'Relevance'. Change that to either 'Price: low to high' or 'Price: high to low".
Most people go for the first option of low-to-high. Selecting this option, will show you a list of books on aromatherapy and they will be arranged from cheapest to most expensive.

I would have to say that you really can not beat on line prices. You would find really good prices for books on " Aromatherapy" at places such as Amazon.com and I would even try Play.com first.

I first always check with my local library. Depending on where you live you may find a great selection.

My top picks for finding and buying books is Amazon, Barnes and Nobles, and Schuler books. If you have a Barnes and Nobles or Schulers near you they can also order books for you. I have found all three sites usually have free shipping and are prompt at getting your order out quickly.