drop list matching corosponding values from another set of cells or tab

I used to create pretty intensive spreadsheets a few years back and knew excel very well. Unfortuantely that was several years ago and I am now stuggling on what should be VERY simple.

I have a spreadsheet which I created to keep track of expenses. The fields are.

DATE | NAME | ITEM | COST | QTY | SUBTOT |

The ITEM and COST columns should come from a seperate source (other source columns or even another tab).

Currently I have the items coming in via DROPLIST from a list of cells on the same spreadsheet. What I need is the COST cells to automatically fill once something is selected from the corosponding ITEM tab.

ie. My TWO data columns are similar to this.

ITEM | COST
-------------------
MAP | $5.00
PEN | $1.00
LOCKBOX | $25.00

Now if I use the pulldown to select MAP I need the next colum (COST) to show $5.00 automatically.

What am I missing? I have been playing with if statements etc. and running into problems. I know there is a simple way to do this, but I am drawing a blank.

Any help would be greatly appreciated.

THANKS!

PS - I attached a quick screenshot of a basic idea of what I am looking at, although I would prefer to put the data on a second tab.