In Badugi the best hand has 4 cards of 4 different suits and the overall lowest combination wins. Aces are low so the best possible badugi hand is A-2-3-4 in four different suits. Since Aces are low, the highest card in Badugi is a king and the worst possible hand is all four kings.
If you do not have 4 different suits then your lowest combination of different suites will be your best hand. Having A-2-3 of 3 different suits is the best 3 suited hand available, but remember a Badugi (4 suited with no pairs) beats any three card hand.
What about pairs? If you have A355 (all different suits) then your hand is really A35, which is a three-card hand. This is because you can only use one of the paired cards.
If any two cards in a hand are the same suit or rank, then one of the cards is eliminated, leaving the player with a three-card, two-card, or one-card hand. Any player with a four-card hand automatically beats any player with fewer cards in their hand. If players have the same number of cards in their hand, then the hand with the lowest high-card wins.
In cases where a card or more is removed, the hand is scored as if the highest possible card is removed, unless there is a case where a card is both of the same suit of one card and of the same rank of another. Then, only one card need be removed, leaving the best possible valid hand.