Keep an eye open for Harbor Freight. On some holidays they have their 2hp DC unit on sale for about $200, plus a discount coupon for 20-25 percent, which brings the cost down to about $160. This is the model with a 5 micron bag. This should be rolled outside for use as it emits fine particles galore inside your shop and that's extremely detrimental to your lungs. For in the shop use, you need to add a Wynn Filter, with will cost about as much (or more) than the HF dust collection unit itself. Grizzly has a filter unit for the same DC that has a built in beater bar to clear the filter from time to time.
I have two of these, one for the shop, (with the Wynn filter) that now sits outside the shop in a covered area. The other still has the bag and is in the garage so I can roll it outside for use. With a chip collector in line, it's amazing how much cleaner my shop is since I made the move outside. Here's a pix, BTW, I've shortened the hose from shop to chip collector to reduce direction changes. Stick points out that the HF unit isn't as well made as other, name brands, and that in the long haul, they're a better value. I'm 75, so my long haul is fairly short, and I find they work fine.
It is possible to dramatically increase air flow and DC effectiveness by replacing the HF unit's impeller with one from Rikon. It's a tight fit, but doable. But for my purposes, the HF unit does the trick.