GameStop offers the Valve Steam Controller for $34.99. Plus, coupon code "SAVER" bags free shipping. (Amazon offers it for the same price for Prime members only.) That's $5 under our March mention of a refurb and the lowest total price we could find for a new one now by $15. It's compatible with Windows, Linux, Mac OS, and Steam OS.
Also available is the Valve Steam Link for $34.99. Opt for in-store pickup to avoid the $3.99 shipping fee. That's also the best deal we could find by $15. The Steam Link allows you use your home network to play Steam games on your TV.