Gap in the jean problem lol?

my my hips are 35/36 in and my waist it 24/25 in. when ever i buy jeans they fit my thighs and hips but then there is a huge gap in the back of my pants. if i get jeans with out gaps then they barley fit my thighs(no im not fat im in shape). can anyone tell me a good brand of jeans that can fit me that isn't expensive? im 5'7 and 121lbs. thank you sooo much:):)