The answer is a bit complicated, but it usually comes down to fair market value - what someone else would be willing to pay for them.
I want to pass on this fantastic chart by Kay Bell over at her fantastic site Don't Mess With Taxes on how to value common clothing and household goods donated to charity.
Clothing
Values from lowest to highest average
| Clothing article | Women’s attire | Men’s attire | Children’s attire |
| Blouse, shirt | $2 to $12 | $2 to $12 | $1 to $8 |
| T-shirt | $0.50 to $4 | $0.50 to $6 | $0.50 to $2 |
| Sweater | $3.75 to $15 | $2.50 to $15 | $1 to $8 |
| Skirt | $2 to $12 | -- | $1 to $6 |
| Dress | $4 to $28 | -- | $2 to $12 |
| Slacks | $3.50 to $23 | $2 to $15 | $1 to $8 |
| Jeans | $4 to $21 | $4 to $21 | $2 to $12 |
| Jacket | $4 to $12 | $6 to $12 | $1 to $6 |
| Business suit | $5 to $30 | $10 to $30 | -- |
| Overcoat | $7 to $40 | $7 to $60 | $3 to $20 |
| Shoes | $2 to $25 | $3.50 to $25 | $2 to $8.75 |
| Swimsuit | $4 to $12 | $2.50 to $12 | $1 to $6 |
| Handbag/briefcase/backpack | $2 to $40 | $2 to $40 | $1 to $15 |
| Evening attire | $10 to $60 | $10 to $60 | -- |
Household Goods
| Item | Low to High Value | Item | Low to High Value |
| Kitchen utensils | $0.50 to $1.50 | Washing machine | $40-$150 |
| Glasses/mugs/cups | $0.50 to $1.50 | Dryer | $45 to $90 |
| Plates | $0.50 to $3 | Color television | $75 to $225 |
| Pots and pans | $1 to $3 | Radio | $2 to $50 |
| Kitchen/dinette set | $40 to $900 | Stereo | $15 to 75 |
| Sofa | $30 to $200 | VCR/DVD player | $8 to $15 |
| Coffee table | $10 to $65 | Records, CDs, DVDs | $1 to $5 |
| End table | $4 to $50 | Books, paperback | $0.75 to $2 |
| Throw rug | $1.50 to $12 | Books, hardcover | $1 to $3 |
| Chair | $5 to $100 | Desk | $25 to $140 |
| Bedroom set | $250 to $1,000 | Computer monitor | $5 to $50 |
| Dressers | $20 to $60 | Printer | $5 to $150 |
| Bed linens | $2 to $8 | Lamp | $4 to $50 |
| Quilt, bedspread | $3 to $24 | Vacuum cleaner | $15 to $65 |
| Blanket, afghan | $2 to $15 | Lawn mower | $25 to $100 |
| Bath towels | $0.50 to $4 | Bicycle | $5 to $80 |
| Air conditioner | $20 to $90 | Puzzles, board games | $0.50 to $3 |
| Heater | $7.50 to $22 | Stuffed animals | $0.50 to $1 |
| Electric stove | $75 to $150 | Ice skates | $3 to $15 |
| Gas stove | $50 to $125 | Roller blades | $3 to $15 |
| Microwave oven | $10 to $50 | Tennis racket | $2 to $5 |
| Refrigerator | $75 to $250 | Golf clubs | $2 to $25 |
More here:
- Bill
