What is the value of a 1928 F US 5 dollar bill with a red seal?

As of 04/2015 approximate prices are:

Circulated: $8 to $13 depending on the bill's condition

Uncirculated: $35

FAQs:

Red Ink

In 1928 the Treasury adopted standard colors to distinguish the four types of bills that were then in circulation. A red seal and serial numbers identify a bill as a United States Note, a banknote issued directly by the Federal government instead of through a bank. US Notes were printed for for about a century but were eliminated in the 1960s in favor of issuing all currency as Federal Reserve Notes.

Serial Numbers

A bill's serial number is a counter and a security feature. In most cases it doesn't affect a bill's value or help to identify it. Some collectors specialize in bills with low serial numbers (e.g. 00000005) or unusual patterns (12344321) so these can bring above-average prices.

DISCLAIMER: The values quoted are market averages as of the date shown, but may be different for an individual bill due to variations in quality and other factors. Also the wholesale (buying) price of a bill will be less than the selling (retail) price. A reputable currency dealer will be able to give a more accurate valuation based on an in-person inspection.