$10K is not bad considering you get the pump, diffusers, and enough 5/8" weighted line to do the job.

Air Max Kit and some accessories~$6K
1575 foot of line ~$2- 3K
Installation - ???

You should talk to Scott (AKA esshup, here at the PP) and see what he can do for you. Here's his website...

https://hoosierpondpros.com/Contact_Us_5EHB.html

Does the $10K include any installation? You can piece a DIY kit together pretty easily and save a chunk of money, but that would rely on coming up with a cheap or free cabinet. The pumps size you need and the required weighted hose Is-What-It-Is. You can't get around that, but if you can construct a ventilated shed (or dog house) for it and scrounge up some plumbing parts...quality pump/s and line should not cost more than $5K (I think that is on the high side). Then I'd throw my savings at a few more diffusers, more line, and a bigger pump (Note: I like to over do things and you cannot have enough aeration for water surface conditioning compared to just DO imp[rovements). I would personally prefer diaphragm diffusers over the tube style. What you are paying for with the Airmax system is convenience, the cool rock-like cabinet, and the assembly labor. If your lucky, the installation was included, but that's not a big deal to do yourself if you have a boat and some basic handyman skills.

Fish on!,
Noel