There's a variety of products out there for cargo solutions.
As you may have already seen, Yakima and Thule are the two most well-known names to cargo accessories, however, checking out other brands such as Rhino Racks would be a great start. If anything, you local roof rack dealer may have some insight as to what solutions are available for mounting your paddle board.
amazon has them for $234
Subaru I found them for $209 = $28 shipping
SUP Taxi does not come with cross bars, they mount onto cross bars. yes its expensive. $200 (cross bars) 200+ for foot pack $269 for SUP Taxi, and additional locks for the foot pack $60.
For my 14' displacement race board
currently I use Thule aero racks and Dakine pads.
Locking straps with integrated cables.
Subaru has their cross bars for $150. There are some other brands out there that have cheaper cross bars that are not aero design $50 bucks and up.
Thule sup "shuttle" ( not SUP taxi) $150. ( it fits most cross bars.)
I have a complete Thule rack on our Crosstrek, but for by outback I picked up an Inno rack for s fraction the cost and its the same, except for some nice additions.
I use Malone cradles for my kayak. Just as nice as the good Thule or Yakima ones at half the price.