well if your REALLY into saving money, stock yfz arms and shocks CAN work with a bit of modding...you can look up the details of it on here somewhere, that would definately be your cheapest bet. if you look enough you could about get everything you need for under $100.
otherwise cheapest way out would be ASR a-arms for about $350 like they said, and works...but personally i wouldnt spend money on works shocks, they're barely better than stock, try to find some used elkas.
2005 yfz450
wiseco 12:1 piston, hotrods rod and crank, cam mod, gytr exhaust, uni air filter, tag bars, holeshot HD rears, razr fronts, tusk nerfs, pro armor xc bumper, acerbis handguards, gytr graphics and seat cover, ac grab bar, *much more to come!*
1993 cr250
in the middle of a makeover, many mods, fresh rebuild, will be for sale soon...pm me!!
2003 300ex
-renthal bars, uni filter, turf tamers, race cut fenders, 250r AC stadium bumper