Note, I am brand new to all this too, so I'm speaking from no experience. Here is what I plan on using to hold my crickets to assist with feeding.

Live Crickets and Supplies: Lee's Kricket Keeper Cricket Care & Dispensing Kit for Reptiles

I am also looking at Firebelly toads for my 4 year old daughter.

From the reading Ive done, they are social animals that get depressed if they are alone. At least 2 is a must. To be safe don't put more than 2-3 in a 10g or 4-5 in a 20g.

I plan on 3-4 in a 20g high. I just bought my tank at Petco's dollar a gallon sale yesterday. Unfortunately this was the last day of the sale.