I know that if I go back to China, hotels that are around 300+ can be about $100 for two nights. Besides mainland China, where else can I stay? Is there anywhere in the US for under $100 a night? Is Vegas the only place where that might be possible?
So does a hotel in China that costs three or four hundred for two nights meet the reimbursement requirements?
If you just want to avoid paying anything out of pocket, you can start by sorting the booking platform by total price after taxes, from lowest to highest. But keep in mind that many of the cheaper rooms will still add a resort fee or city tax at checkout, which could easily push the final total over one hundred.
Actually, the Vegas you mentioned might be an exception, since on weekdays and outside of holidays there really are quite a few rooms for just a few dozen dollars a night—though once you add the resort fee and taxes, it often comes to more than a hundred. What really matters isn't the listed price, but whether the final charged amount can be covered by reimbursement. Also, some places have low room rates but are out of the way with high transportation costs, so when you add it all up, it may not be worth it.
It might work during the short off-season, but during peak season it's basically hopeless.
I'm not so sure Vegas is the only option. Some smaller and mid-sized cities have cheap chain hotels outside of convention periods too, but the question is whether you're willing to make a special trip just to get a hundred bucks reimbursed—time, airport transportation, and meals all add extra costs. If you already have travel plans, it makes more sense to use it along the way; forcing an extra night just to get reimbursed might actually end up costing you more.
Next, start by listing the few cities you visit most often, then check the total price after taxes for your target dates in each one, paying close attention to whether there are resort fees, parking fees, and cancellation policies. If you find an option close to one hundred, it's best to take a screenshot of the price breakdown, then check it against the reimbursement terms to confirm it qualifies. Don't just look at the starting price shown on the search page—that usually isn't the final amount you'll pay.
You're asking about using it up without paying extra, but you may first need to confirm whether the reimbursement rules allow splitting or using it across categories. Some cards automatically apply the credit per transaction, while others require booking through a designated portal, and the range of hotels you can choose differs greatly between the two. If you can clarify exactly how your card triggers the reimbursement, the advice everyone gives will be more accurate.