I'm in the process of building a auto-vacuum system for a large commercial pool, based on a Polaris 280, and found that some Amazon resellers have Polaris 280 components on clearance. I purchased a complete 280 unit, plus the booster pump, for about $490 ($324 + 166). This was over $150 below my WHOLESALE cost for these units.
Here are the links:
Now, this is not for everyone -- but if you have an aging pressure-side Polaris, and want a new cleaner, or if you need a new booster pump, this is a great opportunity.
Watch the pricing however. My guess is the prices on each component will jump $100 - $200 once the seller has cleared out excess inventory.