depending on your sourcefullness, you can build one fairly cheap and yet make it good quality.
i built mine. the trailer: a small boat trailer given to me free.
the 8" H beam: free for some landscaping work
the engine: 18hp b&s i had laying around
the hydraulic tank: 18 gallon tank my son built for me at his shop
the cylinder: paid $125 for a 6 x 24 someone had
the control valve: a prince 3000 paid $79
the pump: barnes 2 stage paid $279 (11/22 i think..i'll have to check)
the hoses: $100
the steel: bought from onlinesteel.com for $125
the welding: all done for free
the wedge: bought for $22 from northern
many other parts i got from scrounging around. true, steel is expensive but there are also some great deals out there if you look for them. i have pictues of the progession of my splitter. sure, the time you spend designing and looking for parts and building it
might outweigh walking into a store and just bringing one home, but for me it was the challenge and the fun of doing it.
http://s89.photobucket.com/albums/k228/mga_01/