You should scroll down to about 3 days ago in this forum where someone was having problems getting a Jacksons to eat silkworms. Some chameleons will devour them, but seems to me like most will only eat a few and then stop. I think younger animals will eat more of them (without stopping), but before you buy too many, give them a shot with a smaller amount and make sure your chams like them. If you have access to a mulberry tree, go ahead and get more if you want (alot of insects is usually only a little more expensive than a handful of insects). A good place to get silkworms would be Mulberry Farms (I think it's www.mulberryfarms.com), but also you can get bigger ones at Amierican Cricket Ranch and I think LLLREPTILE. If you buy eggs at Mulberry Farms, you get a TON more for your money.
-Tyler Stewart