Multi-function formula (=IF)

[Suzimc78]

I would like to write a formula for shipping cost in Excel 2003, for specific shipping weights. Each product is a different weight. The result is in a new column.
What formula would I use for this column? The figures below are hypothetical.

A1 is 4 lbs. Shipping is $6.00
A2 is 8 lbs. Shipping is $12.90
A3 is 10 lbs. Shipping is $16.00
A4 is 15 lbs. Shipping is $24.00


Formula for the column is ?

If A1 is greater than 1 lb. and less than 5 lbs. then shipping cost is $6.00 or
A1 is greater than 7 lbs. and less than 10 lbs. then shipping cost is 12.90 or
A1 is greater than 9 lbs. and less than 15 lbs.then shipping cost is $16.00
A1 is greater than 14 lbs. and less than 18 lbs. then shipping cost is $24.50