Claudek, if you have the time and knowledge, yes use the ebay API and php, it's not difficult. But if you want results faster, use BANS, you won't regret.
Is Bans a php script which can be altered to different products, and used again and again on different domains?
Not sure about the license for using it on multiple sites, but yes that's pretty much BANS in a nutshell. I haven't used it but from what I hear it's easy to setup.
BANS IS VERY EASY TO SET UP. if u need installation i can do it for you.. all i ask is u buy via my affil link and i will install it all for you