I debated this deal but for me it doesn't seem worth it. I'm close to the airport so I save generally $42 on round trips (there are a few cheap fares which are exceptions). Discount den seems to save about $10 each way. My friend and I were talking about it and I think if someone flew Frontier frequently but it wasn't convenient to buy tickets at airport, then the deal may be worth it.

There are fees to have a real carry-on or reserve seats but this is similar on others like Spirit and I understand that legacy carriers have created fares with similar restrictions. If you can manage with just the personal item it might be worth it. Otherwise you have to factor in the bag fee each way when comparing costs.