$600 for a 2KVA transformer sounds mighty high. Grainger sells one retail for less than $500.

http://www.grainger.com/Grainger/items/1H723

Which confirms my initial estimate that your should be able to find one for $200 to $300. Dig around through e-bay and used electrical equipment houses and you might find one for $100. But then again you seemed to have found a cheaper solution.

I used to heartily recommend a sine-wave inverter but increasingly I have found that modified, stepped, wave inverters to run just about everything pretty well. A few hurricanes back I ran my PC off of a fairly cheap 700w modified sine wave unit inverter drawing off my vehicle.

The key IMO was that I built the PC with a good quality and over-sized power supply. The PC draws a small fraction of what the power supply is rated for. Watch the ratings because many are listed as being far more capable than they actually are.

Generally consumer electronics are going to be the most sensitive to fluctuations in power quality and waveform. Your best bet may be to set yourself up with a small, but still fairly expensive, true-sine-wave inverter to run those few bits of delicate consumer electronics you really need during an emergency. But to run everything else on a much less expensive stepped wave inverter.

I have run pumps, portable power tools, small appliances, and a variety of lights off of the my little inverter. I had a small fluorescent light flicker and hum to the point I wondered about its safety but other, larger, fluorescent lights handled it well enough. They hummed a bit more than normal but started and ran well enough and the ballasts didn't heat up. A few degrees above normal, showing they were working harder to use the squared-off waveform, but not enough to worry about.

I have found precious few devices that require a true-sine wave to operate well enough. Of those that wouldn't work well using a modified sine wave inverter only a very slim fraction were devices that are vital during an emergency.