New front springs (I prefer Traxxion...$125 plus installation but you can find cheaper like Progressive) and disable your anti-dive valve. If you want to improve the rear, a new shock and spring will run
around $600 plus installation.
Dan is definately correct. However if you wan't to go really cheap you can get a significant benefit from just installing heavier straight wound
Front and Rear springs. Haven't checked the prices of these parts recently but probably around $350 total and you'll get a substantial portion of the benefits of the much costlier full monty. The most serious flaw in the stock 1800 is WAY
TOO SOFT SPRINGS and WAY
TOO MUCH SAG - generally in the 50% plus range rather than the desired 30%. Thus you 10wallow and either bottom or hit the anti bottoming bumber on any significant bump.
The REALLY cheap but still highly beneficial set up is make sure your rear adjuster is full of oil and run it at 25 plus add the Traxxion front springs.