What is the value of a 1928 ten dollar bill?

It depends on the series, as indicated by the presence/absence of a letter after the date, and the condition of the bill. Some ranges: 1928 Gold seal $30-$85 in average condition $250+ uncirculated 1928A Green seal $30-$65 avg $125-$160 unc 1928B Green seal $20-$50 avg $75-$100 unc 1928C Green seal $65-$200 avg $1000 +/- unc