Conditional IF Function by Name

I have this spreadsheet I'm making for Christmas to keep track of my wifes and my purchases. I'm having problem with a formula tho and I'm not sure how to go about this. Basically I have a "name" column. As you will see. At the bottom I have "total spent on cristina" "total spent on jon"

I need like an "IF" condition that will look at that name column and say, "if name is Jon" add up the amounts in the "total cost" column according to what Jon spent. If name is cristina, add up her amounts.

Might make sense if you look at what Im doing. Thanks in advance...really... its appreciated!