One thing I have found when trying to use Dot Matrix before now is that if it is set up as 'Generic Text Only' in Windows, your reports will look terrible, (it's virtually impossible to get the right line spacing on the report and so it comes out with unpredictable extra spaces between some, but not all lines.
If you set the printer up with it's own driver, you should get reasonable quality, but the printing will be slower than generic text.
We use OKI Microline 395 printers - they are very reliable, have a long duty cycle and are not too noisy but cost about £800 each, they will print up to 6 copies on NCR (non-carbon) paper.
Mike
PS is this because the client already has stationery that they want to use? - It might be better in the long run to go for laser stationery and just print several copies.