I suggest starting with a 6mm and 3mm 2 flute TCT flat bottom and the same in ball end,together with a 90degree engraving tool for V-carving and similar.Be sure to get an engraving tool and not just a 45 degree bevelling cutter.The other thing you need is to get hold of some software and learn to use it.E.ven if you don't produce Gcode,you need to explore all the possibilities and alternative approaches to arriving at the desired result.Do you have any feelings about which software to use?For signs,you might find F-engrave good and it costs nothing,as a result of Scorch's generosity.
I use Freecad myself for design and toolpaths and it is very capable,if a little quirky,and has a post processor for Mach 4 in the latest version.There are lots of tutorial videos on youtube.There is a lot of enthusiasm for Fusion 360 among hobbyists-although that has waned a bit since they abandoned the free usage model.If that doesn't appeal,the Vectric products have a following and don't cost too much in the greater scheme of things.Cylindrical work may be a bit beyond your controller if it necessitates adding a 4th axis.Incidentally,adding your location to your profile would be helpful for some recommendations.