How much would this tattoo generally cost... i know its hard to estimate?

i already have fox very detailed on my right shoulder.. i wanted to add to it in a tribal design down my back in a diagonal design down to the lower left side of my back.. its fairly detailed but still basic lines and few shaded spots. it is my own hand drawn design. there wont be color because i prefer to see my skin through it. the one on my shoulder cost 100 and this will be about 5X that size... but the way theyre detailed is completely different.. any estimates?