Here's a link to a CD or download version of the factory manual for less than $25:
2003 Honda Civic Hybrid Factory Service Manual on CD-ROM
And on Amazon we see this:
2003 2004 Honda Civic Hybrid Shop Service Repair Manual Book Engine Drivetrain : Amazon.com : Automotive
Call me old-fashioned, but I strongly prefer the physical copy. You can take it to the car.
Based on what I'm seeing in the reviews about Haynes' manual for that year of Civic, I can't recommend it. I might, simply because it'll have everything you need for all the chassis and passenger area stuff, and a fair portion of the drivetrain and probably the brakes. But too many reviewers are saying the Haynes people phoned it in, and apparently the Chiltons manual is exactly the same. So bite the bullet, get the factory manual. I know you want inexpensive, but if you can avoid even one modest trip to the shop, you're ahead.