Hello xKomon, it's nice to see that you enjoy GBF, which truly has been quite the entertaining Gundam series.
Regarding the ever adorable Beargguy-san III, you may find the kits at most retail outlets but I personally recommend visiting the specialized hobby store, namely:
Hobby Art Gallery - Dhoby Ghaut OR Macherson
Orbe Station - Jurong East
Personally, Bearrguy-san III kit is very basic, in comparison to many other High Grade Gundam kits, so the price should be between SGD30 - SGD40. However, it is a very popular release and I'm not surprised if it's sold out. So, please check by calling before you head down to buy.
The kit is molded in the colours seen in the anime, so you do not need to go and spray the kit, especially since this will be your first kit for now. You just need to apply the stickers for the eyes and no cotton stuffing is required
You can also ask them for the Gundam Panel Line Markers - Black colour, as featured in that video.
I hope you and your GF enjoy making your cute kits.
PS: The person in the video used a Hobby Side Cutter, which gives a cleaner plastic parts cutting than if you used a nail clipper or similar.