You can download the games at various sites and forums, but I highly suggest you buy the game from a site like J-List.
At Touhou Wikis you can find the English Patch for the games.
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As for now, all the Touhou games (6 to 18) are only available for Windows computers and Mac (running bootcamp). Besides this, the games 1-5 are only available for download on PC-98 computers, which were dropped due to incompatibility. I'm honestly pretty unsure over how to download games 1-5, but you can find the official games on Steam, and can buy Touhou 6 on Amazon. (make sure to look for a trusted seller)
Touhou 1-5: PC-98 Touhou >6: Windows Spinoffs: Windows
Although pirating is pretty popular amongst the Touhou community, most games would fall under $14 CAD and the spin-offs being $12.
About 110, including Reimu's turtle and an unnamed catfish in one of the games.
Internet.