For the television, Logitech harmony hub has an official integration, works well, and is popular.
You would also need a streaming device, such as a Roku stick or Chromecast.
For other devices see the following ( this is a clickable link):
As far as pricing, $40 is a typical retail price for many devices. In addition, there are a lot of different kinds of options that you can use with SmartThings. If you’re willing to order from gearbest, which is a retailer which imports from China, you can get the Xiaomi line of sensors which typically cost about $12 each. However, these are not certified devices and operation may be quirky. There are a number of community members who are willing to take the risk that they will stop working at some point just because they are so inexpensive. You can read more about them here:
As far as certified devices go, you just have to keep shopping around. Devices do go on sale and there are sometimes ones at Home Depot or Lowe’s. I think all the sensors that I have were $22 or less. But I shopped a lot of sales.
Community members will post deals that they see in the deals category of the forum, so that’s a good place to look as well