We have bags in all kinds at 20 dollars.这句中为什么用at?

we have shirts in all c_______ at 20 dollars each 上.We have sweaters in all colors （at） 5 dollars. We have sweaters in all colors at 50元each 为什么用in和at We have shirts in all c______ at $20 each.The We have ashirts in all c( ) at $20 each We have great bags ( )only 5 dollars. We have sweaters in all colors at $e_. We have sweaters in all colors at $50 e_. 单句改错1we have sweaters in red,green and black at 50 dollars e we have sweaters ( )all colors ( )￥50 A.in 、at B、at、in C、in、 We have T---shirts at only 10 dollars.(改错） We have great bags for just 4 yuan.请问:可以用at代替for吗?