Non proprietary backup software

Can anyone recommend a non-proprietary software so i can incrementally backup about 20 of my office computers onto 1 single computer.

Ive found many kinds of softwares that do this in a proprietary format but im really not a fan of that format so am still in the hunt for one.

Im willing to pay around ?150 max if its a good one, the better/more reliable the company the better- would prefer if it wasnt anything free just incase it was something dodgy.

thanks, and any help would be really appreciated