If Formula assistance

After trying to get this If,Then to work I am stumped. Can someone please look at this and tell me what I am doing wrong?

=IF(S2<25000,R2=$100,IF(S2>25000,S2<50000, R2=$150, IF(S2>49999, S2<100000,R2=$200,IF(S2>99999,S2<250000,R2=$250,IF(S2>250000,R2=$300,0)))))

S2 contains the population value
R2 is where the amount is displayed.

I want the Then to display nothing.

Hi JLCS,
Is the result of the formula supposed to be in R2?
If so the formula needs to be in R2 and you will have to remove the "R2=" part of the formula.