Reddit mentions of Cougar Attack X3 Mechanical Gaming Keyboard - Cherry MX Brown - Backlight

The Bottomfeeder Guide to MK Shopping is a good place to look, if a bit US-centric. Azio MGK L80 and Cougar Attack x3 are on Amazon and both have media keys.

1. There are no RGB keyboards under $99. They may be "rainbow" (i.e. different colors LED per row, but still 1 LED per key rather than 3 for full color) for cheaper. If you want cheap, go mono.
   
   
2. There is no specifically "gaming keyboard". The so-called "optimized response" sprouted by Razer is pseudoscience. There are keyboard designed with "gamerz aesthetics" but scientifically the difference is minimal to none.
   
   
3. I am confused as to who are you buying this for. If you are buying it for him, and he's so cheap he can't even afford $50, why are you worried about Cherry switches or not? The cheapest MKB w/ Cherry on the market is $70-80. the Cougar Attack X3, but if you plan to go used you can find everything from old Razer Blackwidow (non-backlit) or old CM Storm Trigger to Corsair K60 (only some keys are mechanical) that it'd be pointless to recommend... It'd be up to you to do research on the fly.
   
   
4. Cheapest MKB on Amazon is Aula Demon King TKL at $38, and ReDragon Kumara TKL at $40. Both with Kailh or Outemu blue switches NOT Cherry.
   

Magicforce 108 with Gaterons then, or this if you really don't wanna pay the extra $10.

Just look around on Amazon and read some reviews. There are so many affordable mechanical keyboards these days and with a budget of $60 you have lots of options if you choose to go mechanical. Here are some good mechanical options/brands:

https://www.amazon.com/Redragon-K556-Mechanical-Keyboard-Aluminum/dp/B01NAI2TXC/ref=sr_1_9?ie=UTF8&qid=1505072205&sr=8-9&keywords=red+dragon+keyboard
Red Dragon is rising star in peripheral market, they are geared towards wallet conscious consumers, but offer some good products.

https://www.amazon.com/Razer-Blackwidow-Ultimate-2016-Refurbished/dp/B01LXOPFWP/ref=sr_1_8?ie=UTF8&qid=1505072792&sr=8-8&keywords=razer+keyboards
Here is a refurbished Black Widow Ultimate from Razer, which as you probably know is a renowned reputable brand. This offers green back lighting like you requested and is right at the $60 mark.

https://www.amazon.com/Cougar-Attack-Mechanical-Gaming-Keyboard/dp/B01938BWZG/ref=sr_1_28?s=electronics&ie=UTF8&qid=1505073256&sr=1-28&keywords=CHERRY+MX+keyboard
This keyboard lacks green or rgb lighting, but does offer Cherry MX switches in either blue, red, or brown. Cherry MX switches are German made mechanical switches and are generally regarded as the best switches you can get. I personally own a Corsair K65 RGB (the oringal, not the lux) with Cherry MX Reds and its fantastic, but at $170 bucks its out of your price range and the price has become inflated anyway.

If you really value led lighting non mechanical keyboards are the best way to get your RGB fix. While not as fast or in my opinion as nice to type on there are many wonderful options in the way of membrane keyboards.
https://www.amazon.com/Corsair-Gaming-K55-Keyboard-Backlit/dp/B01M4LIKLI/ref=sr_1_3?s=electronics&ie=UTF8&qid=1505073832&sr=1-3&keywords=RGB+keyboard
If you don't want to go mechanical this Corsair 55 is a great alternative. This does not offer per key back-lighting, but has some great lighting effects that beat out most mechanical keyboards in this price range. By the way, this keyboard is only $50.

There you have it my super long comment regarding keyboards. As I said before, spend some time on Amazon researching keyboards in more detail, but the ones I listed are in my opinion some of the best options in your price range.

If you can live without the red backlighting then the Magicforce 108 may be worth looking into.

Edit: I guess it would have been wiser to link to this guide for cheap keyboards. It actually has a keyboard that meets your criteria, the Cougar Attack X3. The only potential worry is that it has a very unusual non-standard bottom row.

https://www.amazon.com/Cougar-Attack-Mechanical-Gaming-Keyboard/dp/B01938BWZG/ref=sr_1_1?ie=UTF8&qid=1495670960&sr=8-1&keywords=cougar+attack+x3