Reddit mentions of Kingston Digital 16 GB Class 4 microSDHC Flash Card with SD Adapter (SDC4/16GBET)

Raspberry Pi 2 Model B

Supports CEC. Comes with 4x USB 2.0 slots, an HDMI, quad core ARM A7 processor, 1 GB RAM, and an ethernet port. Also has GPIO pins but I don't know of any Kodi related uses for them. It is an extremely low power device (uses about $3 worth of electricity per year) and requires nothing to keep it cool (e.g., no fans blaring in the middle of your favorite movie).

Base cost is $35. Requires a microSD card, an HDMI cable, and a microUSB charger, all of which can be purchased for approximately $5 each. An existing microUSB charger, such as from your cell phone or a device like a Kindle or Chromecast can be used, of course. Optional components include a case ($10-$20 or 3D print your own), USB wifi dongle ($10+), and an external hard drive ($50+). A few companies put out bundles that include a Raspberry Pi board and various components such as this basic one and this more complete one. A wireless keyboard ($20+) can also be handy. Product links are provided as examples; there may be better deals or smarter purchases to be had.

You'll then want to use a minimalistic Linux distro such as OpenELEC or OSMC, both of which are designed specifically to run Kodi and have optimized builds for a Raspberry Pi. OpenELEC seems to be more popular and is what I use myself. Installation is easy -- you just download and write to your SD card (oh yeah, you might need an SD card reader, $5). If you'd like you can also install a "real" Linux distro and install Kodi in that as you would on a regular desktop computer. You can either store your media on an external hard drive connected to the Raspberry Pi or on a separate computer or NAS and share your files over your LAN.

Pros:

• Cheap base cost
  
• Low power
  
• Very hands off after initial setup
  
• CEC! Use your TV remote to control Kodi
  
• Hardware decoding for h264
  
• As it is full-fledged computer you can easily add in additional software such as emulators, a web browser, etc.
  
• More of a DIY solution (may be a con)
  
  Cons:
  
  
• A few plugins (typically they are Windows dependent) and more computationally intensive skins may not work
  
• May get pricey if you need to buy all the separate components
  
• Can not handle 10-bit x264 (aka Hi10p; rare outside of anime fansubs) or HEVC (aka h265) files.
  
• No 4K output, max resolution is 1920x1200
  
• More of a DIY solution (may be a pro)
  

You need:

• A RaspberryPi - newer versions have a better CPU (but you can get a Zero for $5). If you want to play N64, go with a newer Raspberry Model B.
  
• A +5.1V micro USB power supply (for RetroPie, a 2.5A one works well)
  
• A USB Keyboard
  
• An HDMI cable
  
• A gaming controller of your choosing (USB cord if you can/otherwise bluetooth)
  
• An SD card - these can come pre-loaded if you shop around
  
  Optional:
  
  
• A nice case (according to OP's friend, Legos).
  
• SD Card Reader/Writer (if you didn't buy an SD card preloaded; some laptops have them)
  
• A bluetooth dongle (for PS3/PS4/XBox/XBoxOne/etc.)
  
• A wifi dongle (if you don't want a hard wired connection)
  
  Download RetroPie
  
  Follow video here:
  
  https://retropie.org.uk/documentation/installing-retropie/
  
  Might I add, you can setup SSH on the retropie, so you can connect to the machine and upload ROMs without having to use a USB keyboard. Google for old ROMs, I've used LoveROMs in the past.
  
  Total build time ~1-2 hours. Total cost $30 - $65.

I know you said you're pinching pennies, but this 16 GB card is literally the price of a Subway sandwich.

Someone asked me for a parts list via PM. I am a lazy man, so this is a 100% Amazon Prime build:

https://www.amazon.com/gp/product/B00CJGIWIA/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B00T0BH8WS/ref=oh_aui_detailpage_o02_s00?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B001Q13BIU/ref=oh_aui_detailpage_o04_s00?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B00H95C0A2/ref=oh_aui_detailpage_o05_s00?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B007OYAVLI/ref=oh_aui_detailpage_o05_s01?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B007OYAVLI/ref=oh_aui_detailpage_o05_s01?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B004FHO5Y6/ref=oh_aui_detailpage_o05_s01?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B00T2U7R7I/ref=oh_aui_detailpage_o05_s01?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B00DYQYLQQ/ref=oh_aui_detailpage_o05_s01?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B00TIY5JM8/ref=oh_aui_detailpage_o05_s02?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B00ZHF3RHQ/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1
https://www.amazon.com/gp/product/B018JWCX8M/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

I understand. If you do go for a cheap camera this one is about the only option you have left.

It's mostly a lottery if you will get something "decent" that's somewhat reliable or something that where the video looks zoomed in and looks pretty bad. In terms of MicroSD, I found Transcend to be the cheapest sold by Amazon instead of being sold by another seller, which assures you it's not gonna be fake. Transcend is a great brand too.

Edit: I found a Kingston that's also sold by Amazon, although I vaguely remember those cheap models not being compatible with it, not sure.

This SD Card is definitely integral to my human spirit because without it, how will I watch movies on my tablet!?

Well first thing to get out of the way is that I'm a Communist, I was born in a tree outside of Jacksonville, Florida, I have a black belt in ironing, and I can speak six languages including Q, Pluto and Alexander Graham Bell.

This is actually a great cheap project for a beginner to make! Just buy the following:

1. WAV Trigger
   
2. Arduino UNO
   
3. Kingston SDC4/16GBET
   
   You'll also need a trigger/keyboard/switch system to play the sound files. The WAV Trigger can be loaded up with 4096 sound effects/songs of your choosing, and up to 14 can be played simultaneously. You can build your own music instrument for under $100! So even though it doesn't generate square waves, that can be done in Audacity, and you can also use this project in the future to play any sounds you want, from square waves, to piano, drums, Arnold's voice, etc. It's a great soundboard!

Holly Jolly Christmas! :D This isn't an add-on, but it's a small item under $5. If that doesn't work for ya, here's another item.

I loooooooove Christmastime. I am looking forward to seeing all the lights around the neighbourhood... and trees.

Thanks for the contest!

Just booted up a fresh Raspbian install with this and it worked fine:

http://www.amazon.com/Kingston-Digital-microSDHC-SDC4-16GBET/dp/B00DYQYLQQ

I also had an old NOOBS card that was actually a micro-SD adapter, like this:

https://www.adafruit.com/products/102

and that worked fine too (I don't think I got it from Adafruit though, I think it came in a MAKE starter kit).