i think i know what you're asking. for
say this is your 1st sheet:
A1 B1
initial amount to spend $3,120
left to spend $3,015
and this is your 2nd:
A1 B1
Player Name Price
X 78
Y 14
Z 13
the cell with $3015 above will calculate automatically for you if you use this formula:
=B2-SUM(Sheet2!B:B)
a 2nd way to do it if you just want information to just automatically show up on your 1st sheet based on what you did with the 2nd sheet such as player's name, etc:
in your first sheet, click the cell you want the information to show up in, hit the equals key on your keyboard and then click over to your 2nd sheet and left click once on the cell you want the information to be copied from.
once you have that, you can copy and paste that "formula" to the rest of the cells in your 1st sheet. the formula looks like this:
=Sheet2!A1
hope that helps, i'm no excel genius but that's how i would do it.