There are many different types and levels of finishes. Different people have different preferences, needs, desires, limitations, etc. The simplest finish is no finish at all just raw wood. From there the sky's the limit.
If you want a finish that is within your skill set and level of ability then you can still DIY it and save a lot of money. For example, the Santos Rosewood (Pau Ferro) veneer with a French Polish finish to the depth and luster of lacquer (think high end classical guitar) on my N3TL's only cost me a little over $400 in material. Of course there was also the 2-1/2 months of elbow grease nights and weekends to apply the approximately 500 coats of finish. If I paid somebody to do that it would have cost me about $2,800 ($800 for the veneer and $2,000 for the French Polish).
Could I have done it cheaper? Sure, there are lots of nice wood veneers for a lot less than $400/sheet but I wanted to have an heirloom quality piece of furniture my wife would love (she picked out the veneer) as well as a fantastic sounding pair of speakers.
However, a piano gloss finish with automotive paints is beyond my abilities. If I want that, I'm going to have to pay somebody else to do it.
Mike