I have been looking for a original Datsun wood steering wheel to replace the black one in my 280z. I have found some on eBay but I feel like they are charging quite a lot for them. What year cars had these steering wheels and where could I find one?

70-73 for sure. Ebay, Craigslist or a junk yard. The prices are going up because they are getting harder to find

Early steering wheels did not have holes in the spokes.  They are usually more expensive than the later style with holes.  Search the site for many restoration / refinishing topics.