Macro To Retrieve Data From Spreadsheet

On sheet1 I have 6 products in E15:E20 and their prices in AB15:AB20.

I have created userform1:

Step 1. When the form shows I'd like the products in E15:E20 to show under "Product" and prices in AB15:AB20 to show under "Price".

Step 2. The user needs to be able to add a price value in either the "-Disc" and/or "+Fees" fields, from this the adjusted price should show in "New Price"

Step 3. When the user hits "Add", the value under "New Price" needs to show up in AB15:AB20. To complicated this last step (maybe) in cells AB15:AB20 is:

Code:

=IF($R15=0,"",IF(ISERROR(SUM(INDEX(Data!$V$3:$Z$114,MATCH($E15,Data!$U$3:$U$114,0),
MATCH($B15,Data!$V$1:$Z$1,0))))+
SUM(INDEX(Data!$AO$2:$AS$7,MATCH($T15,Data!$AN$2:$AN$7,0),MATCH($B15,Data!$AO$1:$AS$1,0))),"",
SUM(INDEX(Data!$V$3:$Z$114,MATCH($E15,Data!$U$3:$U$114,0),MATCH($B15,Data!$V$1:$Z$1,0))))+
SUM(INDEX(Data!$AO$2:$AS$7,MATCH($T15,Data!$AN$2:$AN$7,0),MATCH($B15,Data!$AO$1:$AS$1,0))))

So whatever value is entered into "-Dsc" or "+Fees" needs to be added and/or subtracted from this formula.

I don't know much about vba, the best I could come up with is:

Code:

Private Sub cmdclose1_Click()
Unload Me
End Sub
Private Sub cmdadd1_Click()

[Code]......