As a graphics artist, no cover artists do not "promo" the book. Our job is to create your cover, not promote your book. Promotion of the book is your publisher's job and your agent's job. If you are EPub or POD, that then is the onus that lays on your shoulders.
My rates are 250 or lower (depending on what it is you want and what technical support you require. For example, conversion to PDF, help uploading to something like Lulu.com, changes to an existing cover, custom cover, ect). I also provide a front cover, 300DPI a la cart for around 75 to 100 CND.
I low ball for a reason, I believe everyone should have quality for an affordable price. I've been a graphics designer since 1999 and have been running my own company since 2004 officially (unofficial since 1999 after I graduated with my bachelors from college).