Drop down list leading to data in a further drop down list

Hi Excel Forum et all, Tearing my hair out over functions problem, re-drop down lists etc.
I've got a list of data, which is the subject of a drop down box. When i click on the drop down box of 5 items (which all relate to different and increasing floor areas) i will choose one of those options, which i want to then lead to either another drop down box containing a set of 5 different costs or default a set cost depending on which choice i select from the first drop down.
I've gone througn about 10 otr so online tutorials, following the examples exactly, but none works. I've tried VLOOKUP, IF, MATCH & INDEX, but nothing works.
I did get one result from selecting the top choice on the first drop down, which selected the top choice in my second list, using the IF function, but couldn't get it to work when selecting choices 2-5 in my first list and the required 2-5 costs in the second list.
HEEEEEEEEEELPPPPP!!!

Welcome aboard.