Plastiq.com is a service that will charge your credit card and mail checks on your behalf. (With some vendors they also make electronic ACH payments.)

Their usual fee for this is 2.5%. It’s worth it to incur that fee if you’re earning a signup bonus with the credit card charges, or you’re meeting a spending threshold for a bonus.

In April they briefly offered payments with a 1.5% fee if you used a Mastercard. This turned out to be a mistake, but they honored bills that had been scheduled. Since they only accept Mastercard if you’re paying a mortgage I scheduled out a year’s worth of mortgage payments for the miles.

Ariana Arghandewal writes that Plastiq.com is now offering 1.5% on up to 3 payments made in June,

This may be a targeted promotion. If you haven’t gotten an email from Plastiq, go ahead and start a payment. Fee info is on the second to last step, so you still have time to back out if you’re not getting the promotional rate.

I generally advise that it’s not worth it for the ongoing miles without a spending bonus. You don’t want to incur a 2.5% fee to earn 1 mile, you’re buying that mile at 2.5 cents. No mile is worth that.

There is an exception: for business spending companies can generally write off the fee. If you’re paying business bills via Plastiq.com your net cost is 2.5% minus (2.5% * your marginal tax rate). At 1.5% though I’m interested.

Some people who were eligible for this offer had difficulty using it at first, if you’re one of them try again those issues should be fixed.