BW,
The solution I would use is to create a table somewhere out of the way:
In this example I have used I3:I7 and J3:J7
In I3 enter 0
In I4 enter 1
In I5 enter 5
In I6 enter 50
In I7 enter 100
In J3 enter 2
In J4 enter 1.5
In J5 enter 1.3
In J6 enter 1.2
In J7 enter 1
Then in your target cell enter the formula:
=A8*INDEX(J3:J7,MATCH(A8,I3:I7,1),1)
EG