Ben Johnson shares some helpful comments on the need for new missionaries to establish some sort of "setup fund", and why its important to for supporters to give towards this need:

"Imagine you lost everything. I mean everything. Your house may have been hit by a tornado or burned to the ground. What would you need to replace? Furniture, appliances, a new house? There is a lot that goes into having a home that we often don’t think about because we have accumulated what we have needed through the years but what about if you had to do it all at once?

That is basically what a missionary does when he goes to the field. It can vary from country to country as to how much you can bring with you but one thing is the same: there is a lot you have to buy and get when you are there. When we are first married, we usually have wedding showers and gifts that help out a lot but when you arrive on the field, there typically is not someone there to buy a missionary household goods just for being there."