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I was looking through the gift card options for the It's cash back redemption, and I think I'm gonna put mine toward Airbnb - I like that service, have stayed in some nice little places with some nice folks for a really low price, and Discover will give a $50 GC for $45 in cash back. With the double cash back in year 1, that means $450 in spend will land a $50 airbnb gift card for 11.1% return - not too shabby for something that I'm most certainly going to use *and* that's a good value (as opposed to most gift cards for retail and dining: a macaroni grill gift card is nice, but i'd rather take $45 cash than a $50 gift card for the place), I would take that gift card option, that pretty much covers a night for me most of the time I stay at an Airbnb.
You're saying just buy gas cards and take the money you would have otherwise spent on gas and put it in a savings account - I mean, isn't that generally what happens with the money you save by using a gift card?
Personally I don't think Shell is really that great of a redemption, at least around here their gas tends to be on the more expensive side of things. I usually go to QuikTrip, there are a few of them that are convenient for me that consistently have among the cheapest gas I can find - but beyond that, QuikTrip is a Top Tier gasoline provider, and they do use their top tier detergents in all of their grades not just the premium. For me, a $75 Shell gift card wouldn't be worth any more than $70: I just checked Gas Buddy, and the first QuikTrip is 2.26 for standard, 2.78 for premium (i get both in a 1:2 ratio cuz my car is designed for 91 but we have 87 and 93), and Shell is 2.46 for standard, 2.99 for premium. This means Shell is about 7.5% or 8.8% more expensive than QuikTrip. And even for people who don't have QuikTrips, I expect there's something with Top Tier gas that's consistently cheaper than Shell.
This is what I meant by something I'd use that's also a good value. Airbnb I have found competitive room rates everywhere I've looked, and haven't had any real complaints with any place I've stayed yet. I will definitely at some point spend money at Airbnb in the pursuit of saving money while traveling - I can't say the same for Shell.
I was going to say Brooks Brothers with a 20% discount to FV on stuff I'd buy, anyway...but it looks like they no longer offer them (at any price).
Second choice was LL Bean (20%).
I like Chipotle food, but a 10% discount isn't really worthwhile when I can use my CSR for dining.