AWe all know that most brands of cake mix have 3 ounces less in the box than they used to. I have a reciepe that calls for one one box of cake mix plus 3 ounces from amother box. I have a box of betty crocker and wondering if it would come out right if i mixed it with 3 ounces of another brand, ALDIS,that also has pudding in the mix but is a little cheaper costing only a $1.00

Personally I would do it.  The 3 extra oz shouldn't effect the outcome that much.

The other thing is - not knowing exactly the recipe you are considering, I have found that using the smaller weight box mix does not effect my *original* WASC recipe.  In other words, I do NOT add any extra dry mix - just use one box as is and it does not make any difference.