1950 D Series $100

In order for anyone to give you a solid idea of value, you would need to state the condition of the bill.

Free advice dep't:
Off the top of my head, ordinarily I'd make a semi-educated guess and tell you unless it's in mint condition (not circulated), it's not worth more than the face value of $100.

FWIW, however, on E-bay people with similar but not exactly the same are asking between $200-$500 for more rare versions of bills than yours. You should speak directly to a collector..or coin and bill shop.
Note This E-bay ad:

http://www.ebay.com/itm/1950-D-BENJAMIN-FRANKLIN-ONE-100-HUNDRED-DOLLAR-BILL-FEDERAL-RESERVE-SMALL-NOTES-/360470927156?pt=LH_DefaultDomain_0&hash=item53edbdd734#ht_574wt_1124

Furthermore, after Googling your info using the keyword phrases, value of Benjamin franklin $100 Bill, 1950 D series"", I got the following info:

" important to understand that there are different 1950 one hundred dollar bills that accumulate different prices in terms of value, but the majority of them are worth between $140 and $175"

Further investigation reveals that a star on the bill (*) would indicate a greater value., but generally it's placed in the area around which I wrote earlier.

Creases and/or rips and general heavy wear reduces its value down to face value.

The collecting of money (ones, fives, tens, twenties, and hundreds etc.) is called notaphily. While others call it savings.