$5000 to $25000: this level of race is for school board level, county races or municipal races.
$26,000 to $300,000: this level of race can include county seats, aldermanic races, and even state senate races in small and medium states. (Some state senate seats will be more, especially in California, Florida, and New York. These races for state senate can get very large, and even some large mayoral races will exceed this band- for example Chicago and New York City mayoral elections can get into the millions.)
$300,000 to $750,000: this band encompasses most large state senate races, excluding the absurdly large ones, and this is also the starting range for smaller national Congressional races in small states.
$750,000-$10 million: this covers the largest state senate races, most national Congressional races, a few very special mayorals in large cities, and some governorship races. (Although, JB Pritzker this past year spent $300 million in Illinois, and Rick Scott and Meg Whitman spent at least $100 million each out of pocket in their races.)
$10 million to $1.5-2 billion: this covers presidential outliers and the largest statewide and congressional races.