It depends greatly on what stamps they are, what condition they're in, and so forth. You can check out some books on philately from the library for free, or you can have them professionally appraised (which is not free).
the value it will be like this, for 1861-62 the franklin on blue color is around 125.00 in mint condition and 25.00 used, washington in rose is 47.50 in mint condition and 1.67 used
i believe about 100 usd at ebay cause of i collected stamps couple years back, so that is why I believe that but if it has lot of them i bet 1-5 bucks each
