VBA code help

[noobiestnoob]

Hello All, my username aptly conveys my experience with Excel and VBA. I am trying to create a GUI to call out values from a worksheet.

Currently, I have a worksheet (Sheet1) which is a "calculator" page. Sheet 1 pull values from another worksheet (Sheet 2). In Sheet 2, Col A has reference codes (mainly numbers but some have an Alphabet prefixed to the number). Columns B through K are different vendors and they contain the price for the reference codes in Col A.

This is the formula I am currently using to get the price: =IFERROR(VLOOKUP(C7,INDIRECT("'"&B$11&"'!$A$2:$C$22500"),3,FALSE),0),
where C7 is the reference code, B11 is the cell where I pick the vendor name.

I am now trying to create a VBA form, such that I am able to pick the vendor with a combobox dropdown.
Next when I enter in a textbox the reference code, I would like the the cost for that code for that specific vendor autopopulate in Textbox 2

I just do not know how to do this because I realized that I am the noob's noob. All assistance greatly appreciated.
Thanks!