Walmart.com has Gemini SLATE 2 and 4-channel DJ controllers on sale:
Gemini SLATE [walmart.com]
Gemini SLATE 4 [walmart.com]
Gemini SLATE Bundle [walmart.com]
Gemini SLATE 4 Bundle [walmart.com]
Decent reviews for an entry level controller and probably among the cheapest with Serato support.
Next best price I see is $114.51 at newegg.com, don't see the SLATE 4 on sale anywhere. Upgrading to Serato DJ costs $99, so this is a pretty substantial savings for anyone without a full license.
Also, Walmart.com purchases should be eligible for 5% cashback with a Chase Freedom card. Not eligible for Walmart associate discount.