5x Points: Office Supplies, Cell Phone, Cable, PayPal Digital Gifts via ebay
Limits: $50,000 per cardmember year
Cell Phone & Cable
This one is obvious, but autopay your phone and cable bills from your Ink card.
Office Supply Stores
This is less obvious, but office supply stores such as Staples and Office Depot sell gift cards to many other stores, both in-store and online. Staples, for example, sells gift cards to Amazon, Target, Home Depot, Shell, and Southwest Airlines, among many, many others. I can’t list them all here, so visit their stores and websites to see what is available.
Keep in mind that if you are buying gift cards, you might also consider purchasing them secondhand from a reseller. When I do this, I check Gift Card Wiki for the best prices. Depending on the retailer, you can often get a higher discount than 5%. You might prefer this to 5x points, though purchasing gift cards secondhand comes with some risks that buying them directly yourself does not.
Ebay (Gift cards)
For some reason, when you purchase gift cards from the seller PayPal Digital Gifts on ebay and pay with PayPal using your Ink card, you earn 5x points. This is the same play as buying gift cards from office supply stores, but this method provides many more options. Last I checked, PPDG sells over 500 types of gift cards.
Occasionally, PPDG will also sell select gift cards at significant discounts. When this happens, instead of buying gift cards to spend, you can buy them to turn around and sell to a gift card reseller. You might even walk away with a small profit on top the points you earn. When good deals for reselling present themselves, I’ll post them on the blog.
Verizon (Gift cards)
If you are a Verizon subscriber, the Verizon Message+ app has an option to purchase and send eGift cards. The trick is that you can charge them to your Verizon bill, allowing you to earn 5x UR per dollar spent. This is a small play, however, because you are limited to charging $100 per month to your bill.
Some merchants of note are Amazon, Best Buy, ebay, Home Depot, Sears, and Whole Foods. You can find the others listed in the app after you click Send an eGift Card Now!