This is a great way to challenge yourself if you are just getting into soldering or mechanical keyboards. Just realize that you need to not only buy this kit but also
1. the keycaps
2. the Arduino / Arduino clone
3. the header pins (also know that if you want to have the acrylic piece fit you cannot use the socket method of attaching an Arduino on this kit)
4. solder
5. a soldering gun (and a desoldering pump because you will mess up)
6. FLUX PASTE (I have just recently started using this and it makes everything SO much easier to solder
7. a USB (mini or c) cable depending on the Arduino you get
I had to solder it on 3 times and this took me forever to get to work but finally, after a year of on and off messing with this board, I finally got it to work!
It looks like this will be a cheap thing to do, but after you factor in all the extra things you need to buy and the time it will take for all of these parts to get to you, I promise you will be spending a pretty penny. But it is definitely worth it if you like it then you can use all the tools to build your next project!
Good Luck!