Definitely listen to some of the more experienced chameleon owners in here, but I've learned a lot over the last year and I can prove some quick recommendations:
1) I would stop buying from petsmart. They can be dirty from there which is potentially dangerous to your chameleon. I buy my crickets from Joshs Frogs. Honestly they're cheaper pretty much even with shipping. I'm not even joking. It's REALLY close (and shipping is really fast). You'll get way healthier crickets.
2) Your chameleon NEEDS to eat at this age on a daily. I *personally (again listen to more experienced owners* say .....feed what you have for today. Non-gutloaded crickets will still provided at least SOME of what your chameleon needs vs absolutely nothing.
3) 100% get a window feeder. Force it on your chameleon. I promise you if he doesn't like it at first.... he will not let himself starve over it. Force it on him and let him eat these crickets from a window feeder. I would highly recommend you stop feeding him by releasing them into his enclosure. Crickets will poop all over the enclosure, and spread any parasites, or w/e they may have all over the enclosure. Also, they can, and will likely bite your chameleon (hurts him and can cause infection) while he is sleeping.
You definitely want a variety. With that being said it seems some chameleons are way picker than others. I have a VERY picky chameleon (he's never once eaten a dubia, superworm, or anything at all besides crickets, BSFL (and the flies), silkworms (sometimes a moth), and some hornworms (as a treat and I rarely give them to him).
I think you should try some sites (dubia.com, Joshsfrogs.com, Framschams.com(silkworms!) and start buying online. It's way more convenient, you'll find it's really not much more, if at all more expensive (for me... it's WAY cheaper buying online than in petsmart tbh). And.... you're getting higher quality bugs.