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Those costs are figured per pound of sheet metal as a rule, then difficulty and finish factors added such as with stainless steel in a food plant needing to have welded and polished seams, (a #2 finish) and clean out access.
A detailed mechanical drawing is required to even get a fairly close estimate... that generally takes a number of hours or day or more depending on the size of the job. It is not possible to do for the 'just an answer' amount you offered.
If you wish to rate my work so far positively, I can however coach you on how to get good and reliable costs for the job.
Let me know if that interests you, we can go from there.