I wana know what is depend guess how much cost for the Tattoo portrait of 2 my kids!?

I m define have already 7th tattoos so it ll go be 8th soon to have planning get tattoo portrait of my 2 kids picture that I would go with upper arm for it on july 1st as well. so I m define want know wonder if it could customer tattoo can do make up 2 in 1 size like Large portrait picture of my 2 kids that also it would go with ink black/gray old fashion way what I want it. so I wonder how much cost for tattoo portrait size large plus black/gray is ??? If it is should ve guess how much cost is for tattoo portrait size Large upper arm is?