Real Life Gardening Math To Help Save Money and Time


I want to purchase edging stones for several garden beds in my yard. There are a few ways this can be accomplished.

  • Look on for sale pages for others who are redoing their landscaping and getting rid of their edgers. This would be the most cost efficient but also take the longest time. It would also involve the most driving. Cost: about $1 each this way.
  • Go purchase new ones from a local garden center, with kids in tow, buying what I can fit into my vehicle each time. This is how I have been doing it for other blocks in my garden. I can fit about 40 in my vehicle at one time. The limiting factor is behavior us the little people coming along for a ride. If they are in good moods, the trip is easy. If not, I would rather not go. This adds time as you can not necessarily control how other people feel and react. It also requires multiple trip to the garden center and wear on the vehicle. It is good if you need a couple here and there. Not so much when you need a lot if something. Cost: $2.18 each, plus approximately _____ 40 minute round trips in time and gas
  • Go purchase new ones from a local garden center and have them deliver to my house. This would save on wear to my vehicle, save on gas, and require only one trip to the store. However, there is a delivery fee involved and all the stones would be delivered at one time. Cost: $2.18 each, $75 delivery fee, plus a 40 minute round trip in time and gas.
  • Hire a landscape company to come do the work. It should go without saying, this would be the most expensive option as you are not only paying for the product but also their time to do the work. Cost: this would vary depending on landscape service, time of year, etc. One I talked to charges $10 per foot to put in new beds.

While thinking through these options I came across another bit of information – if I buy the edgers in bulk I get a lower price. Then the question arose. How many edgers would I need to purchase at the bulk price to cover the cost of delivery? Let’s take a look.

Delivery cost/(regular price of edgers-bulk price of edgers) = $75/($2.18-$1.96) = $75/$0.22 = 340.9

As I do not plan on buying 0.9 of an edger, I am going to round it up to 341 edgers. After that many purchased I would be saving and have the cost of delivery covered.

How much do 341 edgers and delivery cost? You can do this two ways right now, each getting the same answer.

  • 341*$2.18=$743.36
  • 341*$1.96+$75=$743.36

It is only after this point that you will need to use the second equation above to figure out your cost.

To figure up cost versus savings you would do the following:

  • number of edgers x bulk cost + deliver fee = # edgers x $1.96 + $75
  • number of edgers x non-bulk price = # of edgers x $2.18
  • To compare the savings you would take the second answer and subtract the first to find the difference

But, what if I do not want to buy 341 edgers yet still want them to be delivered? That is a valid option as well. At this particular store you need to purchase 288 edgers to receive the bulk price.

  • Buying fewer than 288 edgers: # of edgers x non-bulk price plus delivery fee = # edgers x $2.18+$75
  • Buying more than 288 edgers: # of edgers x bulk price plus delivery fee = # edgers x $1.96+$75

The prices and delivery costs, or even the option to have them delivered, may vary at your store. If that is the case use your numbers in place of mine to find your totals.

Also, please remember My Dear Aunt Sally – multiply, divide, add/subtract.

Happy gardening!