Some are more or less than that. Most sales have a name that reflects previously owned children's items. You may or may not want to name your sale. Others only advertise as children's or kid's consignment sales. Unless you have a small sale you will need recruit people to help check out, place items on racks, place signs for advertisement, etc.
People sign up to help in exchange for even earlier shopping privileges.
This is a very cost effective way to obtain help. You need to know how many check outs you will have. One checkout will probably be fine to start with. But as sales grow there is a need for multiple checkouts. Many sales have grown to such a size that they accept credit and debit cards.