a bowl of water and 100 crickets?? no, don't think that will work. Even if your chams drink from a bowl (which is very unusual) what happens when poop gets in the bowl and a cricket drowns and begins to decay? You then have seriously contaminated water. When are you leaving? Do you have a reliable friend who can come in daily to turn on your dripper, mist the cages and put some crickets in a cup? I assume you do not house them together?
Paying a pet store is almost sure death. How about an employee from the store who knows reptiles (if you can find one). And one other consideration is trusting someone (a stranger) in your home.
I am sure others have dealt with this and hopefully will come up with some setup options, but even if you get it all figured out you need a trusted friend to come in regularly just to make sure everything is OK. If your power goes out and your times get all messed up they need to be reset, etc.
Not trying to freak you out but hopefully you are not going for a while and you can work something out. Maybe someone on the forum lives near you. Another option is to contact your local vet and/or herp society and see if they have someone who can care for them. what state are you in?
good luck!
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0.1 veiled - Luna
0.2 felines - Kyndra and Líta
1.0 African Clawed Frog - Skipper
0.5 Mad. Hissers
0.1 Chilean Rose Hair Tarantula (no name yet)
?.? Goliath Bird-Eater Tarantula (no name yet)