Lot of options are available to correct malocclusion or simply put to align your teeth correctly.
Aligners are one of these. Aligners offer dental correction without having to get braces put on your teeth; and hence are certainly more aesthetic.
Treatment using aligners can cost anywhere between 40 K to 1.5 K depending on the severity/complication of your mal-alignment of teeth and the duration of treatment.
But all malocclusion cases cannot be treated using aligners.
It's best to consult an experienced dentist/Orthodontist to get the best treatment options for your wife.