Different Shipping Rates

[SweetFireHoney]

I set up my store and added UPS and USPS discounted rates as the services.

However, when I look at how much the final shipping is calculated at, it shows $8.03. The same box, with the same dimensions and weight, from USPS Click and Ship is $7.50!!!!!

How do I get the best rate??? I'm selling a cheap product ($9) and need the cheapest way for people to get shipping!!!!!!!!

Thanks