Ours is 1.5 too and I only need like .58/yard. I've been putting this project off for over a year and a half now so it's more than due. We have gone back and forth about just paying a contractor, doing it in brick instead of concrete, yada, yada. I recently got quotes from $600 to $800 so we decided to just do it ourselves. The concrete just came on sale for 20% off at Lowes so we finally made the commitment.
I hand mixed 6 bags last year in 90F weather and nearly died. 7 years down here now and I am still not acclimated to the heat yet.