"Sulit" means something that is worth buying/gives value for your money, something worth doing, some place worth visiting, and so on. In this case the video talks about a mobile phone called "Cherry Mobile Flare X3" and the description says that it costs 10,000 PHP. "Pinakasulit" is the superlative form of "sulit". "Gawang Pinoy" means made by Filipinos. Since there is no object given in the phrase, we have to use the word phone (or product or thing, etc.) Therefore, the phrase means Filipino-made phone that is the most worth buying, or in other words Filipino-made phone that gives the best value for your money.