You know, an 8ft stick of pre-primed 3 1/4" baseboard is only $5.
Construction lumber is $2, and you have to buy a router bit, which is $20 or so, plus all the work, then you still end up with 1 1/2" thick baseboards, when they are normally about 1/2".
If you're thinking of stain grade, buying 1x4 select pine will be close in price to pre-made.
Maybe you're not really saving money making it yourself?
Don't get me wrong, I'm all about making parts yourself, but it's not really saving you money for something like baseboards.