First, if your husband is reporting self-employment income on schedule C as a Santa, this might be a deductible expense on schedule C. If he is not reporting taxable income on schedule C, this is not a deduction. The sewing machine would have to be owned by "him" or "his business" rather than by "you" -- although this is a distinction without a difference if you are filing a joint return.
Second, you can't take any deduction for personal expenses. You would have to show that you only use the sewing machine for this business and would not have bought the machine but for the business; or, you have to have some reasonable documentation showing the percentage of business use and the percentage of personal use, and only deduct the percentage of business use. (Such as a diary where you write down the number of hours each day you use the machine and add up your business hours and personal hours.) If you don't have a reasonable method to prove the percentage of business use, and are audited, the expense will likely be denied.
Third, because this is a piece of equipment expected to last more than one year, it is an "Asset", not an expense, and is subject to rules on depreciation. You can generally deduct depreciable assets as if they were expenses if the total amount is less than $2500. You would list the item as an asset, and then if you qualify to treat it as an expense, Turbotax will tell you that later. You would list it with the percentage of business use that you determined.
