I would really recommend a small Kritter Keeper until it grows some. Your main issue for that size froglet will be food. I will suggest very small crickets if you are determined to do the crickets, but a good alternative would be appropriate sized bits of either Red Wigglers or Night Crawlers. Offer food nightly, it may not eat every night, but offer just in case. It will grow fairly quickly.
Make sure that you use ONLY de-chlorinated water for it's enclosure!! Make sure the temps are 80 - 85 F with a humidity of at least 60% (higher is better). Please be sure that when you do need to handle it that your hands are clean with NO chemicals.....douse your hands with the de-chlorinated water too & then you can touch him. He WILL get larger and when he does, biting is almost a guarantee.......LOL. Gently scoop the frog up from behind to avoid a chomp.

I can't possibly place ALL the advice you're going to need in one post, bu I will try to answer what I can as often as possible. I'm sure everyone else with experience will be valuable sources of information & help too!!

Good Luck!!