Yes, get the right power adapter for your hub. I agree, it's very poor for the original maker NOT to include the adapter. They are just trying to keep their selling price down to get more sales, counting on the idea that many users will not realize the adapter is needed. They are competing, in reality, with many hub sellers who make NO provision for extra power. There are so MANY hubs on the market with no power of their own (I like to call these passive hubs) that rely solely on power (limited) from the host's USB3 port. Often these latter are marketed under misleading terms like, "Bus-Powered Hub!" which implies that it has power available of some sort, but really says indirectly that this power is ONLY from the USB Bus (host port).
Look on your hub near the port for a power input requirement like "12VDC / 3A". Look closely at it for the design of the connector, and for a label beside it showing the polarity of the connector - something like an indication that the center pin is Positive or Negative. Then you can find a power adapter that has the right connector and power rating. It really does not have to be from the hub's maker. A slightly higher amp rating is quite OK. Actually, slightly lower also is OK IF you do not ever plan to use all of its ports. However, there is one caution here. SOME hubs I have seen also include one or more ports called CHARGING ports, intended to use to charge up devices that include batteries. There are many such devices on the market now that claim you can recharge them from any USB port and you can - BUT the charging rate done this way is very slow because of the normal limit on USB power from a port (0.5 A from USB2, 0.9 A from USB3). So some hubs include NON-standard "USB" ports that can deliver up to 2.0 A current for charging purposes. If your hub has one of these, the power adapter you get needs to allow for this extra requirement.
If you'd like more help finding an adapter, post back the exact maker and model number of your hub, with any power label note you can find on it.