Design (or use clip art) a heart and print out on iron-on paper per directons on the package.
Cut out the heart and iron the design on the muslin bag (per directions on the paper package)
Add lavender to the muslin bag.
Tie a yard of string to the washer.
Use the helium tank to blow up a balloon, attaching the first one to the string on the washer.
Blow up the rest of the balloons and attach each one to about a 1 yard section of string, tying them to the washer as you go.
Place the washer in the bag of lavender and knot the muslin bag closed.
Notes
I know some people are just not using helium at all or it’s too scarce to find. If that’s the case, use something like these balloon sticks!Just skip the heavy washer for the sachet (to make it into a balloon weight) and tie the sachet to the bottom of the sticks.Another option is using a tiered balloon stand. You can use whatever balloons you want and don’t need the string.Place one or a few lavender sachets (the weight would still be good if you are setting this outside!) around the base.If balloons aren't floating, they may be too small (there isn't enough helium inside to support the weight of the latex). Try using a larger balloon.You also may need to use lighter string. Curling ribbon usually is light enough but, again, will depend on the size of the balloon.The costs for this craft would be to get started. But once you have these items you can make multiple bags so the cost per item goes down. The helium tank alone is about $40. You can always skip that part and take them to Party City or the grocery store to inflate.