what the....
are bumpmap textures ?

Bumpmap texture make your textures looks like 3d.

so ... is it good to buy ? does it look good ? and how should a good bumpmap look like ?

bumpmap texture items are items you buy after you already have everything else you want to customize your tori. Something you buy just before you start spending tc on collector items.
They look ok, not rly a must have. But they are not compatible with some tb versions or shaders (I think they don't work with ray tracing on, not sure tho. Imo ray tracing adds a better effect for free than bumpmaps for tc. Best ask some staff member to explain will it work for your situation.
As for how good bumpmap should look, read this tut and make them yourself.

Hope I helped

yes it helped a lot thx missuse...