Let's look at some sample components, keeping the guidelines we've developed in mind. All prices are from the December 1996 "Computer Shopper" or their website at http://www.netbuyer.com (check this site out -- its search facilities are pretty good). Prices and vendors have been selected to represent what's generally available out there.
A: P55TV PCI with Pentium 166 and AHA 2940 SCSI on board: $740 from Treasure Chest Peripherals.
B: Same P55TV with Pentium 133: $520
C: Same P55TV with Pentium 100: $420
D: Same P55TV with Pentium 75: $380
E: 2 16MB 4x32 SIMMs: $208 from Memory Etc.
F: Seagate 1050MB Hawk 2XL: $350 from Insight Direct.
G: Seagate 2149MB Hawk 2XL: $480 from Insight Direct.
H: "Jumbo" Mid-Tower case + power supply: $40 from Sam's Computers.
I: 6x SCSI CD-ROM from MicroXperts: $160
J: Hitachi CM1587 15" 1024x768 color monitor: $375 from Automated Tech Tools, Inc.
K: ASTVision 7L 17" 1280x1024 color monitor: $400 from Tredex
L: Trident Microsystems 9440 1MB PCI SVGA (1024x768): $31 from Hi-Tech USA
M: Cirrus Logic CL-GD54M30 1MB PCI 1280x1024: $39 from MicroXperts
N: Dalco 1.44 floppy: $43.50 from Dalco Electronics
O: Dalco 1.2 floppy: $58.50 from Dalco Electronics
P: Seagate MS4000R-SB (4GB SCSI internal DAT): $300 from Global Computer Supplies
Q: Americomp 3-button mouse: $5 from Americomp
Now let's put these together into sample system configurations.
First, the deluxe system (A+E+F+G+H+I+K+M+N+O+P+Q): $2824. That's pretty far off our $2000 target, but now let's strip away as much as we can.
If we drop the 1.2MB floppy (you'll never use it!), the secondary disk, and then downgrade to a 15" monitor with 1024x768 resolution, and drop back to a Pentium 75 (D+E+F+H+I+J+L+N+O+P+Q), suddenly the price is just $1892.50.
Now, when you reflect that vendors of desktop systems buy in volume and get the parts up to 40% cheaper than you can even at mail-order, you can see that coming in under $1500 with a Pentium-75 system shouldn't really be very difficult at all.
Even without a system vendor's volume discount, moving back up to a Pentium 100 (C+E+F+H+I+J+L+N+O+P+Q) makes our price $1932.50, still below our $2000 target. But the parts list above is just intended as an example -- it wouldn't actually be a good idea to build your box by separately assembling pieces like that. It's better (and usually cheaper) to go through a system vendor.
There are several things you buy by doing this. One is the vendor's ability to buy in volume and carve its margins mainly out of the volume discount it gets from parts suppliers (this is especially important for big-ticket items like the motherboard and disks). Another is expert assembly. A third is the pre-shipment burn-in. And then, of course, there's the warranty -- a very reassuring thing to have in case your brand-new machine succumbs to infant mortality in spite of that burn-in.
Once you've designed your configuration, you should get quotes from two or three different system vendors. Any vendor who can't generate quotes for a custom configuration, or resists giving a quote without a buy commitment, is not worth your time -- find another.