Unfortunately, almost every exterior mod is gonna cost some buckage. The cheapest will be to color the front badge on the car. $2.50 for some double sided tape and some model paint. Otherwise, a tint-job. New springs (& struts) to drop the car a bit. Wheels and tires. After that, look at body kits. There are few available stateside. There are some awesome ones from Japan, but they are a bit pricey. Check the discussion in this forum on new front facias or something like that...
Good luck, and enjoy!
'98 2.5 GT Wagon