[header] How to improve the sound of your stereo system for less than $100 [title] Keep all of your source material clean. [step] Dirt or oil on your cds or vinyl lps will keep them from sounding their best. Cleaning them regularly costs very little and can make a tremendous difference in the sound quality of your system. 
Vinyl can be cleaned with either mild soap and water or a mixture of alcohol and water. Cds are best cleaned using a commercial cd cleaning spray and a lint-free cloth.