The Ocooch website is a little quirky.  I could not get the drop downs for size and width to work consistently to check out the prices.  What species and widths did you get?  My local HDs and Lowes' do have some 1/4" and 1/2" stock of pine, red oak and poplar (used to carry maple but not any more) but IIRC, the widths are only up to 4", but you can always glue up wider panels.  I think that the pine also comes in 3/8" thickness.  

--Nathan, TX. Hire the lazy man. He may not do as much work but that's because he will find a better way.