Here's a fun one. Incentive formula in tiered structure.

I'm working on this and as simple as it is, I'm having a major brain fart tonight and forgetting all my education on this from school.
Basically what I am wanting to do, is be able to put in last years sales under the LY column (example attached) and have the incentive structure auto calculate what the potential bonus would be if a 5% increase is met, 10%, 15%, 20%, 25%, and 30%. The way this works is noted above PLUS 1/4% of total sales. (.25% of total sales, not 25%).
So between 25k and 50k with a 10% increase would result in .25% of total sales plus $150.
Anybody who could get me on my way, it would be greatly appreciated!
I usually love doing this stuff but for some reason, I'm drawing blanks tonight. This old age stuff is for the birds!