The items are supposed to be valued at “fair market value” - which is usually interpreted as what you could sell the items for at a garage sale, or maybe what a thrift shop would sell them for. Obviously there is a big difference between these two values, and caution says to choose a realistic value, preferably on the mid to low side. You also have to take into condition the condition of the item, it’s desirability and marketability. The Salvation Army has a valuation guide, as does the Helping Hand of Goodwill.Be cautious of using too aggressive pricing. There is a product called “It’s deductible” which alleges to give market values to items. Don’t use it. The values are sometimes way out of whack, and a financial publication tested the product several years ago and found the values to be in excess of what new replacement items could be purchased for at some discount stores. Don’t rely on something that gives you inflated values which could be a flag for an IRS audit. Be conservative in valuation.