I'm not sure what you mean by a moyu yj. There are Yuxin 3x3, 4x4, and 5x5. All quite nice puzzles, in black plastic, plus a white plastic 3x3. The 5x5 is in a plastic box and comes with extra stickers. Prices for Yuxin puzzles are:
White 3x3 $6
Black 3x3 $7
Black 4x4 $12
Black 5x5 $15
I would sell all of them for $35 plus shipping (probably about $6 in the US).
Looks like roughly $13.50 for one cube, $22.50 for two cubes. It would go down per cube if you get more, but still fairly steep. A 3 lb box would be about $34.