Take the Butterfly Hero pledge and you'll get a free butterfly garden starter kit. Now I'm no lepidopterist, but I know a butterfly starter kit involves two butterflies who realllly like each other and a few milkweed flowers. Thankfully this freebie includes the seeds to start growing those flowers!
It turns out the monarch butterflies are in trouble and need more milkweed. So, pledge to grow the plants and help save the butterflies. In exchange, you'll get a free starter kit from the National Wildlife Federation. They're like the Federation in Star Trek, just without all the space ships!
This was previously offered in March 2018 and died extremely fast. I wouldn't put off signing up this time.