Thanks for the insight thus far. Here is the details of what I'm trying to do.

I'm trying to book to business class tickets from Detroit to Barcelona in March. I spoke to Delta and that will be 300,000 miles. With the 30,000 bonus miles I will get for getting the new credit card, I will still be about 65,500 miles short of the 300,000. Therefore, I'm trying to get the additonal miles by the end of the month before (like mentioned above), the mileage price goes up.

I explored buying economy tickets and upgrading it to business class with miles, but those economy tickets would cost $3,000+ while the actual business class ticket costs $4,500, so there's really not much benefit/difference in the price. Therefore, I decided I might as well just book the entire flight on miles.

If anyone has any further advice, it would be greatly appreciated!