One thing to factor in is that ones region can really affect the cost of wood. For example, birch is sited as being a substitute for maple as it gets more expensive, indicating that birch is a less expensive alternative. Here in Ohio, both soft and hard maple are less expensive then Birch. Also in Ohio, western red cedar is hard to find, and when it is available also tends to be expensive. An alternative to WRC that is common here is Aromatic Cedar, which I have used on a couple occasions.
Getting GOOD douglas fir can be a challenge. In this region of the country, it is very common to be used as dimensional lumber for home building. The problem with that is all too frequently it hasn't been fully dried. This makes it very prone for movement, that is sometimes extreme. (We have all seen the banana shaped 2x4's at Lowes!)
Also, choice of wood comes down to personal taste, which can also affect our perceived value of wood. Since red oak is easily sourced from home centers, it is a wood many of us got started with. I used it a lot in my early years of woodworking. I can't stand to use it now. For open grain woods, I tend to prefer using ash over oak, which in this region is actually less expensive than oak (though I suspect in the coming years ash will become much more expensive, no thanks to the emerald ash borer)
For maple, if you are looking for a cost effective solution, many suppliers sell ambrosia maple for less than soft maple. Ambrosia maple has tiny bore holes from the ambrosia beetle. The result is over the years bore holes have allowed water in to stain the wood, creating an interesting "figured" effect.
A couple years ago my supplier had a sale on 6' long (vs the normal 8'-12' lengths) cherry boards of various widths. The sale brought the board foot cost down to a little under red oak (rough sawn, not home center stuff). Cherry is my personal favorite wood to work with, so I snapped that deal up pretty quickly.