That really depends what you want to get into. Helicopters are the broadest brush stroke in fire; they do bucket work, fly meals and supplies in and out of the fire, do patrols and oversight, pick up and drop ground troops, and so on. On any given fire, a helicopter may be expected to all of those, and it's the helicopters that usually time-out, rather than the fixed wing aircraft. When fixed wing aircraft sit, the helicopters will be flying, often to the exclusion of tanker assets.
Fifty to seventy five grand in helicopters, for a season...many operators pay daily rather than hourly, but the way pilots get paid varies greatly between operators. The government makes contracts between themselves and the operators; the government doesn't tell operators what they must pay the pilots, who are usually subcontractors, rather than employees. Some firms employ pilots year-round, doing things other than fire in the off season. Some don't.
In fixed wing, usually one does just a single mission, whether it's air attack, flying jumpers single engine air tankers, point to point and fire patrol, or large air tankers.
Your best bet to find a job doing fire work is an air attack platform. Some have exclusive-use contracts, while most work on a call-when-needed basis. They range from Cessna 337 Skymasters and piston Twin Commander 500's, to turbo commanders, Cessn a 340's and 421's, and some king air platforms. All air attack platforms are operating in a public-use capacity, but are required by contract to be fully Part 135. Pay seems to average around seven grand a month in the summer, but can be higher, depending on the operator.
Single engine tanker work wont' be an option unless you have considerable tailwheel experience and low level mountainous experience, and generally you'll need a background in the Air Tractor 802. Pay ranges from three to five hundred an hour.
Large air tanker positions will be extremely few and far between, and you should plan on ten or more dedicated years trying to get your foot in the door before someone hires you...if you're extremely lucky. Those jobs are had to come by.
The best pay in tankers is with the CalFire (California Division of Forestry), with some positions being nearly year-round.
The "super-tanker" positions are almost a non-starter, with only a couple of airframes, and a very tenuous future.