Most ecover template designs are going to be in a version of Photoshop or similar since they use 'layers'. If you don't own Adobe Photoshop, then you can also use the free Gimp software to edit your templates from Content Sparks.
There are instructions inside the ecover templates folder for editing and converting to 3D.
We recommend using eCoverAuthority to render your edited template into a 3D version. You can also design your covers in that software and it is a one-time lifetime fee:
You can design your ecovers right in eCoverAuthority any way you want. You could use our designs for inspiration, or get someone on a place like fiverr.com to design one for you.
Another alternative is to give a person on fiverr.com the template you like best and ask them to edit it. There are hundreds of people who charge around $5 to do Photoshop editing. They'll charge extra to render it into a 3D version. However, if you're going to do a lot of covers over time, then eCoverAuthority is worth the investment.
For using people on fiverr, we suggest supplying them with your own royalty-free stock photo to make sure it is used properly, according to the photographer's terms.
We usually get our stock photos from Deposit Photos, but you can also find ones that are free for commercial use on places like Pixabay.com and Unsplash.com.
It's definitely worth getting your own branded layout done that you can use over and over for every cover. And if you do one in eCoverAuthority, you'll be able to edit it right in there.