You should research the ebay springs on here, you probably wont read many good things. Are you looking for just a drop or improved handling, both? I'm sure you can get ebay springs to fit but if they are lower than stock, they will quickly wear out your shocks and your ride quality and handling will suffer. If the springs say they will fit 00-05 you are good, if they are for 06+ then then they will most likely not.
Research the different suspensions in the stickied threads at the top. Save some more money for a setup that will last and handle well; other wise you will not like the results and end up having to put more money into the car in the long run.
If you don't want to spend as much money, but still want a decent drop, look into FRPP springs. I have the progressive springs on my 06, and I like them a lot more than the Eibach Pro-Kit springs I used to have. Including shipping, I got them for about $170.
When dropping a car with new springs you're fooling yourself if you don't get new shocks. Shorter stiffer springs require shorter firmer shocks/struts.
The Ford Racing springs and shocks are relatively inexpensive and provide the best bang for the buck out there (about 300.00 or so delivered to your door). Many FF members will attest to their durability and resulting handling improvements not to mention decent aesthetic improvements.
I've looked near and far on a college kids budget and I'll tell you that the FRPP kit is the best looking/most durable/best handling for that price. You can't beat $300 for 8 pieces of hardware. I helped install them on a friend's 08 and it couldn't have been easier.
Also, the only non-brand name thing you can trust on ebay are headlights/tail lights as far as Focuses go I would say
I sincerely hope that your shocks have been replaced on your car (at least a couple of times) based on that mileage. The average useful life of a shock/strut is 50 to 60K miles. Shocks/struts for 00 to 05 foci will fit all models except wagons (different rear design).
If you're not aware, lowering springs are usually much stiffer springs. This is necessary to offset the loss of suspension travel when the car is lowered. Stock shocks are not designed to properly dampen the stiffer springs and in no time you'll be bouncing down the street somewhat uncontrollably and unsafely. A stiffer spring would also quickly wear/destroy a newer stock shock as well. When you pair a shorter drop spring with a longer stock shock you'll be more subject to bottoming out. Riding on the bump stops gets old real quick and it can also damage the shock's valving making them worthless.
I second that Geezer is a good for reliable advice, he has helped me out too....and was right(just for clarification). They did not mention though that if you do a drop in most instances if not done right you will eat up tires every 6-8 months. Camber becomes an issue.
Also the Harbor Freight tool I am hoping was just a sarcastic joke, although it was funny. Cutting my factory springs for just a drop was the first and worst thing I ever did to my Focus. I ended up replacing all suspension parts except the swaybar in the long run. The cheap way out at the time is not the cheap way in the long run!!! It will cost twice as much as the right way would have been the first time around. Rambleon84 was right on the ride quality suffering. Trust that you have no idea what a bad ride quality is until you have created one for yourself. Interstate speeds are scary when it gets bad and the damage from your cheap decision takes it's toll. It's a money pit if you don't just save the money to do it right!!