Is there anyway to get a free or discounted Discount Den membership?
 

Any promo codes or any other way?

No way to get it for free, even for Frontier Elite, but personally it pays for itself and is well worth it imo depending on where you are based and how much you fly F9

$49 might be steep if you're only doing 1-2 flights a year, but being in DEN I fly them fairly regularly for leisure and have saved a ton, the $49 paid for itself with one flight. For example: going to Cancun in September for $200 RT versus $450 w/o discount den

I agree, for some routes a single round trip can pay for Discount Den. Also, you only have to book the trip when you are in Discount Den to get the reduced fare, the actual flights can be beyond the expiration date. We did this last year, booked flights for four to Orlando and it was set to expire in March, in January or February we booked flights to Cancun for May, which was past the expiration date of our Discount Den but we still got the special rates.