Getting half off your airfare for the next couple years thanks to Amex

So Amex lured me into getting an American Express Platinum card a few years ago with a stellar bonus.  I was lucky another 150,000 points for signing up for the Business version of the Platinum card.  This Business Platinum card currently has a publicly available bonus offer of 100,000 Membership Rewards points--not shabby at all although the spending requirements are quite hefty.  But here's why it might be worth it:

Make $1,950 immediately with minimal outlay

Why might you sign up?  Well, you'll make $2,000 off the bat.  Amex recently enhanced the Business Platinum card so that you can use Membership Rewards points towards airfare at 2 cents per point.  So that sign up bonus of 100,000 points is worth $2,000 in airfare.  Nice.  The annual fee of $450 is more than offset.  And it's pretty easy to get the effective first year annual fee down to $50 per the post in the first link.  Except it's even easier now that you don't even have to buy airline gift cards but instead can buy Amazon gift cards through the MileagePlusX app.  You might balk because to get the full 100,000 point bonus, you need to spend $15,000.  Here's where the next step comes in.

Get half off your next $12,500 in airfare purchases

Why is this even more lucrative?  First, along with making Membership Rewards points more valuable for Business Platinum cardholders, it also made them easier to earn by awarding 1.5X points on purchases over $5,000.  Second, through the end of the year, Amex is offering 2X points on small businesses, including a neat website called Plastiq.  Plastiq lets you earn credit card points by paying bills using your credit card, for a fee.  That includes mortgages, rent, and (better yet) home equity lines of credit.

So draw you could draw down a home equity line, and pay it back using Plastiq.  On a $4,878 payment (i.e. $5,000 including the 2.5% fee to Plastiq), you will earn 12,500 Membership Rewards points (5,000 base points, 5,000 small business bonus points, and 2,500 large purchase bonus points). Your out of pocket cost for the 12,500 points is $122 (that 2.5% fee).  Remember, those points are worth 2 cents each toward airfare, so essentially you are buying the points for a little less than 1 cent each and redeeming them for 2 cents.

The only limitation?  The 2X Small Business Saturday promotion is limited to 250,000 bonus points and runs until the end of the year.  You can shoot for 625,000 total points using this 2.5X opportunity, which is worth $12,500 in future airfare, not counting the sign-up bonus which adds another $2,000 worth of bonus points.  These $14,500 worth of points would cost $6,097.  If you are good at redeeming miles, you could use the points as miles and get even more value.