There is another rebate back for Osmocote plant food. We usually see this once a year and it always works out to be a great deal.
This year they are offering $10 back when you buy a 2lb plant food. The offer is valid through June 30th but please note it is always a good idea to submit rebates as soon as you can.
Also please be sure to print the rebate form out as they often take these away if there are too many submissions.
You can get this for $7.98 at Home Depot right now (just order online and pick up at your convenience)
You can probably find it at Target or Walmart as well.