Somthing like Strong Rubber Bands
cool so cool
There are some website to sell the band online.I have a lists you can try them.
The price of slingshot band set is a little higher.If you just buy the band and leather pouch.Making the band set by yourself that saving a lot of money.
Since bike innertubes can be found dirt cheap and usually free (go to your local bike store and ask for a few discarded innertubes which will end up in the garbage anyways) I would suggest this. This type of rubber I also use cut in cross sections to make millions of rubber bands which last so much longer than most commercial rubber bands. They are not as 'springy' but they have more accuracy IMO.
Theirs a thing called a theraband its good for slingshots
Strip down some bungy straps - the sort used to tie luggage on your car rack.Use strips from am old bike inner tubeStrips from a thin rubber sheet they line babies cots with plated togetherHow many elastic things do you see around you??
I will say that my Dad made me a slingshot using inner tube and it had limited stretch and limited lifespan. Of course this was in the 1980's so there's probably been advancements in tube technology.
Surgical rubber tubing (kind of a yellowish-tan color) works great and is available cheap at hardware stores.
As a passing thought if you want your rubber to retain it's performance then keep it out of the light when not in use and if using several strands it's worth oiling the with a mineral oil or castor oil (no idea where you might find that now a days)
You can use the rubber band strength training bands that can be found in most sporting good isles or stores. Doubled over on its self and you can really make them stronger.
+1 can't be beat. Silicone tube may be slightly better.
Surgical rubber tubing is available at chemists (drug stores) here.
You can buy rubber tubing at most hardware stores and I thought I saw it at Walmart.
Surgical rubber tubing is available on the net. Try Ebay. it make GREAT slingshots.