Translation:How much is it?
Where is this expression used (regionally) ? I haven't really come across it before and I was taught and would generally hear "cuánto cuesta," I started studying Spanish in the US and continued in Spain. To me valer has a strong connotation of value (could be the English influence). Always thought you could say something like: "Este libro cuesta 20 euros pero vale 100". yes, no?
Earlier on when first learning present verbs we were shown how the different conjugations worked. One of them was that it/he/she/you (formal) were all the same. Therefore while the hint may have been incomplete and slightly unhelpful you should be able to infer from it.