Is there a formula for the the following calculation (a to d)?

I have tried the following way but not successful.
=if(a20.01,"1","0",if(a2100.01,"2","0",if(a2200 .01,"3","0".....continued
to d)

a) If the amount is greater than 0.01, than the rate is $1.00
b) If the amount is greater than 100.01, than the rate is $2.00
c) If the amount is greater than 200.01, than the rate is $3.00
d) If the amount is greater than 300.01, than the rate is $4.50
e) If the amount is greater than 400.01, than the rate is $5.50

Thank you very much for your response.