Lowe’s has a pretty good spring promotion going on. Get a free Roundup Extended Control Weed & Grass Killer refill when you buy one for $25.97. Just enter code ROUNDUP at checkout. It would make each one only $12.98 each. The offer is good through 4/22.
If you scroll down to the bottom of the page, you will also see a deal for BOGO free Miracle Gro Shake N’ Feed. You can get them for only $6.14 each. This is also good through 4/22.