Help, my kitten started arching its back inwards and is having problem walking

Hi, my kitten started to do this . He was just okay yesterday tapos suddenly bigla nag arch ng back inwards sabay di na makalakad ng maayos. May alam po ba kayong low cost na vet office? Medyo untimely yung nangyare at sakto lang budget ko. Salamat ng sobra sa tutulong