At that price point, I suspect your best bet will be the Chinese brands. I've used a couple that were very reliable, and better than the cheaper big name brands.
I don't know prices in your country. I'm hoping this post will get the ball rolling with US members.
I've been running 2 Chinese ones for a week. Well designed, but I can't comment on durability.
I don't run powered filters but do have power heads to drive my under gravel filtration. The power heads I'm getting ready to use are Aqueon. Generally Aqueon is considered a good brand especially the QuietFlow 10 LED PRO which is designed for small to medium sized tanks. I would think that a 20 gallon would fit in that range.