Populate data in cell based on drop down list selection

Ok a new twist to my previous question. I have a drop down list with the size of blocks in cell A1, in cell B1 is # of Blocks, in cell C1 I want a unit price to be automatically populated once a selection is made from cell A1, in cell D1 is a cost formula (=B1*C1). I assume that I will need to set up a column of unit prices somewhere else in the spreadsheet so that C1 has something to reference. I'm just not sure what the formula is to insert into C1 so that it recognizes the selection in A1 and populates the corresponding unit price.

Thanks in advance

Or a small variation of this. I have a set of data. Column A1-A6 have a designated item (say numbers 1-6). B1-B6 have a weight that corresponds to the items in column A (say 10, 20, 30, etc). I want to create a drop down list that has the items is column A but when selected the corresponding weight appears in the cell. So if I select 1 then 10 would appear in the cell and so on.

This is just a simple example of a more complex data set.

Thanks