The 2 packs above (100 total ounces of detergent) are on sale for $11.97. There is a $3 coupon on the product page, just scroll down and clip it to take $3 off.
You can use High Efficiency detergent in any washing machine.
Free shipping with $35+ orders or get free 2nd day shipping on all orders with a free trial of Amazon Prime. A prime trial is also free with Amazon Mom (which also gets you 20% off diapers and wipes among other benefits) or Amazon Student. Or you can always share Amazon prime for a fraction of the regular cost in this DDF thread!