I have a favorite and very simple recipe I use with some variations:
1 small box of gelatin (any flavor or match it to the drink mix)
1 envelope unsweetened drink mix
up to a cup of sugar
2 cups boiling water
2 cups cold water (can use fruit juice or pop if desired).
Mix the gelatin, drink mix, and sugar. Add the boiling water. Stir to dissolve. Add the cold water. Stir some more. Let the bubbles disperse. Fill 3 oz plastic cups to about 1/2 inch from the top (I use one of the cups as the dipper). I put the cups into high sided trays and can usually get 18 in a large cake pan. Coincidentally, each recipe fills 18 three oz cups. I cut off plastic drinking straws and when the popsicles are partially frozen (anywhere from 1 to 3 hours after putting in my freezer) I stick a straw in each one (instead of popsicle sticks which can splinter). When ready to eat just warm the cup with your hands and push on the bottom to release the popsicle.
This year there are 5 flavors - 90 popsicles - so far. Black Cherry, Red Raspberry (both favorites), Peach, Pineapple (using pineapple gelatin, lemon drink mix, and pineapple soda - sugar adjusted to allow for the soda); and the mystery flavor of the year (Green Apple/Watermelon). If the mood strikes and I find another flat spot in the freezer I may make chocolate pops using pudding again. I have to find my recipe for that one.
Time to go check and see if the popsicles are ready for their sticks.