The type of software needed will depend on how the image is to be fabricated and integrated into the pavers. If, for example, they are to be cast in relief, they may need to be modeled three dimensionally. If on the other hand, the designs are to be etched onto the surface or pieced together like a puzzle then 2D vector software as has been mentioned will probably work well. In addition to the fabricator’s system requirements, it also may depend on how the original image was created as to the best software and method to use to translate it for production and fabrication. 

In terms of cost, it is largely software specific and both cost and availability may be affected by which system (windows or mac) is being used. With more specific requirements for your project, it may be easier to steer you toward a selection of possible options.

Best,