They are worth 10 cents. There is no collector value to a new coin unless it is a proof set or an error.
As of 12/2008, Numismedia quotes the fair market value (FMV) at $5.00
Unless in mint or proof sets, only face value. They are all incredibly common and unless in a set they are only worth 25 cents. Each state quarter is worth face value, 25 cents each. There is no difference in value between these and regular quarters. If you mean an entire set of state quarters, there are 50 states, so fifty states times 25 cents each mean that an entire 50-quarter set is worth $12.50.
These are current circulation coins and have been minted in enormous numbers - several billion each year. If you found them in change they're only worth face value. If you have a complete set of uncirculated ones, they could be worth 5 cents or so apiece.
The value of a Congressional 1989 6 coin set varies depending on several factors. For example, if the set is in mint condition, it has the potential to be worth $150 or more, while sets in lesser condition are worth dramatically less.
The current average value is $9.00 Issue price was $9.00
Current retail price is $9.00 issue price was $9.00
Issue price was $5.00 current value is $8.00
Current retail value is $9.99 issue price was $9.00
Current retail value is $9.00
Issue price was $11.00 current value is $6.00.
Current retail value is $9.00 Issue price was $9.00
Average current value for an 1981 proof set is about $8.00. The 1982 proof set is the year that is known for the dime to be missing the mintmark.
Current retail price of 14-piece Sliver Proof set is $61.00 issue price was $44.95
Current retail price for the 9 piece silver proof set is $288.00 issue price was $31.95
Issue price was $5.00, current retail value is $10.00.
The 10-piece 2003 proof sets have a current market value of $10.00. Issue price was $19.95.